diff --git a/README.rst b/README.rst
index 2a178e8..c81c701 100644
--- a/README.rst
+++ b/README.rst
@@ -2,22 +2,59 @@ Introduction
 ============
 
 Tools to make managing Plone core releases easier.
+It is a wrapper around ``zest.releaser``, plus it adds some commands.
+
+WARNING: this package is only meant for development of core Plone.
+It may have useful bits for others, but we may drop features and edge cases at any time if it is no longer useful for Plone.
+
 
 Installation
 ------------
 
-To install plone.releaser add it to your buildout::
+Do ``pip install plone.releaser`` or add it to your buildout::
 
   [release]
   recipe = zc.recipe.egg
-  eggs =  plone.releaser
+  eggs = plone.releaser
+
+
+Main usage: release a package
+-----------------------------
+
+In  the `Plone core development buildout <https://github.com/plone/buildout.coredev>`_ go to ``src/some.package`` and run ``../../bin/fullrelease``.
+This calls the ``fullrelease`` command from ``zest.releaser``, but with some extra hooks and packages available.
+
+One nice thing it does: look in the checkouts and sources of your ``buildout.coredev`` checkout and update them:
+remove the released package from the checkouts and update the version.
+
+If you are working on branch 6.1 of coredev, then we check if you also have branches 5.2 and 6.0 checked out.
+There we check if the branch of the released package is in the sources.
+If you make a release from package branch ``main`` and this is the branch used in the sources, then we update the checkouts and sources of this coredev branch as well.
+
+After releasing a package, you should wait a few minutes before you manually push the changes to all coredev branches.
+This gives the PyPI mirrors time to catch up so the new release is available, so Jenkins and GitHub Actions can find it.
+
 
-To make it available in buildout.coredev, run buildout with releaser.cfg::
+Main commands
+-------------
 
-  $ bin/buildout -c releaser.cfg
+Take several Buildout files and create pip/mxdev files out of them::
 
-Usage
------
+  $ bin/manage buildout2pip
+
+Take a Buildout versions file and create a pip constraints file out of it.
+
+  $ bin/manage versions2constraints
+
+Generate a changelog with changes from all packages since a certain Plone release::
+
+  $ bin/manage changelog --start=6.1.0a1
+
+
+Other commands
+--------------
+
+Some commands are not used much (by Maurits anyway) because they are less needed these days.
 
 Check PyPi access to all Plone packages for a certain user::
 
@@ -35,10 +72,6 @@ Pulls::
 
   $ bin/manage pulls
 
-Changelog::
-
-  $ bin/manage changelog
-
 Check checkout::
 
   $ bin/manage check-checkout
diff --git a/news/72.feature b/news/72.feature
new file mode 100644
index 0000000..be1a4ef
--- /dev/null
+++ b/news/72.feature
@@ -0,0 +1,2 @@
+Add buildout2pip manage command.
+[maurits]
diff --git a/plone/releaser/base.py b/plone/releaser/base.py
index a401a2b..2a7f8b1 100644
--- a/plone/releaser/base.py
+++ b/plone/releaser/base.py
@@ -54,3 +54,96 @@ def add(self, package_name):
 
     def remove(self, package_name):
         return self.__delitem__(package_name)
+
+
+class Source:
+    """Source definition for mr.developer or mxdev"""
+
+    def __init__(
+        self,
+        name="",
+        protocol=None,
+        url=None,
+        pushurl=None,
+        branch=None,
+        path=None,
+        egg=True,
+    ):
+        self.name = name
+        self.protocol = protocol
+        self.url = url
+        self.pushurl = pushurl
+        self.branch = branch
+        # mxdev has target (default: sources) instead of path (default: src).
+        self.path = path
+        # egg=True: mxdev install-mode="direct"
+        # egg=False: mxdev install-mode="skip"
+        self.egg = egg
+
+    @classmethod
+    def create_from_string(cls, name, source_string):
+        line_options = source_string.split()
+        protocol = line_options.pop(0)
+        url = line_options.pop(0)
+        # September 2023: mr.developer defaults to master, mxdev to main.
+        options = {"name": name, "protocol": protocol, "url": url, "branch": "master"}
+
+        # The rest of the line options are key/value pairs.
+        for param in line_options:
+            if param is not None:
+                key, value = param.split("=")
+                if key == "egg":
+                    if value.lower() in ("true", "yes", "on"):
+                        value = True
+                    elif value.lower() in ("false", "no", "off"):
+                        value = False
+                options[key] = value
+        return cls(**options)
+
+    @classmethod
+    def create_from_section(cls, section):
+        options = {
+            "name": section.name,
+            "protocol": section.get("cvs", "git"),
+            "url": section.get("url"),
+            "pushurl": section.get("pushurl"),
+            # September 2023: mr.developer defaults to master, mxdev to main.
+            "branch": section.get("branch", "main"),
+            "path": section.get("target"),
+            "egg": section.get("install-mode", "") != "skip",
+        }
+        return cls(**options)
+
+    def __repr__(self):
+        return f"<Source name={self.name} protocol={self.protocol} url={self.url} pushurl={self.pushurl} branch={self.branch} path={self.path} egg={self.egg}>"
+
+    def to_section(self):
+        contents = [f"[{self.name}]"]
+        # { 'branch': '6.0', 'path': 'extra/documentation', 'egg': False}
+        if self.protocol != "git":
+            contents.append(f"protocol = {self.protocol}")
+        contents.append(f"url = {self.url}")
+        if self.pushurl:
+            contents.append(f"pushurl = {self.pushurl}")
+        if self.branch:
+            contents.append(f"branch = {self.branch}")
+        if not self.egg:
+            contents.append("install-mode = skip")
+        if self.path:
+            contents.append(f"target = {self.path}")
+        return "\n".join(contents)
+
+    def __str__(self):
+        line = f"{self.protocol} {self.url}"
+        if self.pushurl:
+            line += f" pushurl={self.pushurl}"
+        if self.branch:
+            line += f" branch={self.branch}"
+        if self.path:
+            line += f" path={self.path}"
+        if not self.egg:
+            line += " egg=false"
+        return line
+
+    def __eq__(self, other):
+        return repr(self) == repr(other)
diff --git a/plone/releaser/buildout.py b/plone/releaser/buildout.py
index 2b42a61..3a68674 100644
--- a/plone/releaser/buildout.py
+++ b/plone/releaser/buildout.py
@@ -1,4 +1,5 @@
 from .base import BaseFile
+from .base import Source
 from .utils import buildout_marker_to_pip_marker
 from .utils import update_contents
 from collections import defaultdict
@@ -13,62 +14,6 @@
 import re
 
 
-class Source:
-    """Source definition for mr.developer"""
-
-    def __init__(
-        self, protocol=None, url=None, pushurl=None, branch=None, path=None, egg=True
-    ):
-        # I think mxdev only supports git as protocol.
-        self.protocol = protocol
-        self.url = url
-        self.pushurl = pushurl
-        self.branch = branch
-        # mxdev has target (default: sources) instead of path (default: src).
-        self.path = path
-        # egg=True: mxdev install-mode="direct"
-        # egg=False: mxdev install-mode="skip"
-        self.egg = egg
-
-    @classmethod
-    def create_from_string(cls, source_string):
-        line_options = source_string.split()
-        protocol = line_options.pop(0)
-        url = line_options.pop(0)
-        # September 2023: mr.developer defaults to master, mxdev to main.
-        options = {"protocol": protocol, "url": url, "branch": "master"}
-
-        # The rest of the line options are key/value pairs.
-        for param in line_options:
-            if param is not None:
-                key, value = param.split("=")
-                if key == "egg":
-                    if value.lower() in ("true", "yes", "on"):
-                        value = True
-                    elif value.lower() in ("false", "no", "off"):
-                        value = False
-                options[key] = value
-        return cls(**options)
-
-    def __repr__(self):
-        return f"<Source {self.protocol} url={self.url} pushurl={self.pushurl} branch={self.branch} path={self.path} egg={self.egg}>"
-
-    def __str__(self):
-        line = f"{self.protocol} {self.url}"
-        if self.pushurl:
-            line += f" pushurl={self.pushurl}"
-        if self.branch:
-            line += f" branch={self.branch}"
-        if self.path:
-            line += f" path={self.path}"
-        if not self.egg:
-            line += " egg=false"
-        return line
-
-    def __eq__(self, other):
-        return repr(self) == repr(other)
-
-
 class BaseBuildoutFile(BaseFile):
     def __init__(self, file_location, with_markers=False, read_extends=False):
         self.file_location = file_location
@@ -316,7 +261,7 @@ def pins_to_pip(self):
             new_data[package] = new_version
         return new_data
 
-    def to_constraints(self, constraints_path):
+    def to_pip(self, constraints_path):
         """Overwrite constraints file with our data.
 
         The strategy is:
@@ -351,7 +296,7 @@ def data(self):
         sources_dict = OrderedDict()
         # I don't think we need to support [sources:marker].
         for name, value in self.config["sources"].items():
-            source = Source.create_from_string(value)
+            source = Source.create_from_string(name, value)
             sources_dict[name] = source
         return sources_dict
 
@@ -360,7 +305,7 @@ def raw_data(self):
         sources_dict = OrderedDict()
         # I don't think we need to support [sources:marker].
         for name, value in self.raw_config["sources"].items():
-            source = Source.create_from_string(value)
+            source = Source.create_from_string(name, value)
             sources_dict[name] = source
         return sources_dict
 
@@ -396,6 +341,38 @@ def rewrite(self):
         new_contents = "\n".join(contents)
         self.path.write_text(new_contents)
 
+    def to_pip(self, pip_path):
+        """Overwrite mxdev/pip sources file with our data.
+
+        The strategy is:
+
+        1. Translate our data to mxdev sources data.
+        2. Ask the msdev sources file to rewrite itself.
+        """
+        # Import here to avoid circular imports.
+        from plone.releaser.pip import MxSourcesFile
+
+        sources = MxSourcesFile(pip_path)
+        # Create or empty the sources file.
+        sources.path.write_text("")
+
+        # Translate our data to pip.
+        sources.data = self.raw_data
+        sources.settings = {"docs-directory": "documentation"}
+        if "remotes" in self.config:
+            remotes = self.config["remotes"]
+            for key, value in remotes.items():
+                sources.settings[key] = value
+            for source in sources.data.values():
+                source.url = source.url.replace("{remotes:", "{settings:")
+                if source.pushurl:
+                    source.pushurl = source.pushurl.replace("{remotes:", "{settings:")
+                if source.path:
+                    source.path = source.path.replace("{buildout:", "{settings:")
+
+        # Rewrite the file.
+        sources.rewrite()
+
 
 class CheckoutsFile(BaseBuildoutFile):
     @property
@@ -454,6 +431,30 @@ def rewrite(self):
         new_contents = "\n".join(contents)
         self.path.write_text(new_contents)
 
+    def to_pip(self, pip_path):
+        """Overwrite mxdev/pip checkouts file with our data.
+
+        The strategy is:
+
+        1. Translate our data to mxdev checkouts data.
+        2. Ask the msdev checkouts file to rewrite itself.
+        """
+        # Import here to avoid circular imports.
+        from plone.releaser.pip import MxCheckoutsFile
+
+        checkouts = MxCheckoutsFile(pip_path)
+        # Create or empty the checkouts file.
+        checkouts.path.write_text("")
+
+        # Translate our data to pip.
+        # XXX does not do anything
+        checkouts.data = self.data
+        # This is the only setting that makes sense for Plone coredev:
+        checkouts.settings = {"default-use": "false"}
+
+        # Rewrite the file.
+        checkouts.rewrite()
+
 
 class Buildout:
     def __init__(
diff --git a/plone/releaser/manage.py b/plone/releaser/manage.py
index 6a34519..b235d28 100644
--- a/plone/releaser/manage.py
+++ b/plone/releaser/manage.py
@@ -1,6 +1,7 @@
 from argh import arg
 from argh import ArghParser
 from argh.decorators import named
+from pathlib import Path
 from plone.releaser import ACTION_BATCH
 from plone.releaser import ACTION_INTERACTIVE
 from plone.releaser import ACTION_REPORT
@@ -8,10 +9,11 @@
 from plone.releaser import THIRD_PARTY_PACKAGES
 from plone.releaser.buildout import Buildout
 from plone.releaser.buildout import CheckoutsFile
+from plone.releaser.buildout import SourcesFile
 from plone.releaser.buildout import VersionsFile
 from plone.releaser.package import Package
 from plone.releaser.pip import ConstraintsFile
-from plone.releaser.pip import IniFile
+from plone.releaser.pip import MxCheckoutsFile
 from progress.bar import Bar
 
 import glob
@@ -143,7 +145,7 @@ def _get_checkouts(path=None):
         paths = glob.glob("mxdev.ini") + glob.glob("checkouts.cfg")
     for path in paths:
         if path.endswith(".ini"):
-            checkouts = IniFile(path)
+            checkouts = MxCheckoutsFile(path)
         else:
             checkouts = CheckoutsFile(path)
         yield checkouts
@@ -268,33 +270,34 @@ def set_package_version(package_name, new_version, *, path=None):
         constraints.set(package_name, new_version)
 
 
+def _get_paths(path, patterns):
+    paths = []
+    if path:
+        if not isinstance(path, Path):
+            path = Path(path)
+        if path.is_dir():
+            for pat in patterns:
+                paths.extend(glob.glob(str(path / pat)))
+        else:
+            paths = [path]
+    else:
+        for pat in patterns:
+            paths.extend(glob.glob(pat))
+    all_paths = []
+    for path in paths:
+        if not isinstance(path, Path):
+            path = Path(path)
+        all_paths.append(path)
+    return all_paths
+
+
 def versions2constraints(*, path=None):
     """Take a Buildout versions file and create a pip constraints file out of it.
 
+    If a path is given, we handle only that file.
     If no path is given, we use versions*.cfg.
-
-    Notes:
-    * This does not handle 'extends' yet.
-    * This does not handle [versions:pythonX] yet.
-
-    We could parse the file with Buildout.  This incorporates the 'extends',
-    but you lose versions information for other Python versions.
-
-    We could pass an option simple/full.
-    Maybe if a path is passed, we handle only that file in simple mode.
-    Without path, we grab versions.cfg and check 'extends' and other versions.
-
-    'extends = versions-extra.cfg' could be transformed to '-c constraints-extra.txt'
-
-    I think I need some more options in VersionsFile first:
-    - what to do with extends
-    - what to do with [versions:*]
-    - whether to turn it into a single constraints file.
     """
-    if path:
-        paths = [path]
-    else:
-        paths = glob.glob("versions*.cfg")
+    paths = _get_paths(path, ["versions*.cfg"])
     for path in paths:
         versions = VersionsFile(path, with_markers=True)
         # Create path to constraints*.txt instead of versions*.cfg.
@@ -302,7 +305,40 @@ def versions2constraints(*, path=None):
         filename = str(filepath)[len(str(filepath.parent)) + 1 :]
         filename = filename.replace("versions", "constraints").replace(".cfg", ".txt")
         constraints_path = filepath.parent / filename
-        versions.to_constraints(constraints_path)
+        versions.to_pip(constraints_path)
+
+
+def buildout2pip(*, path=None):
+    """Take a Buildout file and create a pip/mxdev file out of it.
+
+    If a path is given, we handle only that file, guessing whether it is a file
+    with versions or sources or checkouts.
+    If no path is given, we use versions*.cfg, sources*.cfg and checkouts*.cfg.
+    """
+    paths = _get_paths(path, ["versions*.cfg", "sources*.cfg", "checkouts*.cfg"])
+    for path in paths:
+        if path.name.startswith("versions"):
+            buildout_file = VersionsFile(path, with_markers=True)
+        elif path.name.startswith("sources"):
+            buildout_file = SourcesFile(path)
+        elif path.name.startswith("checkouts"):
+            buildout_file = CheckoutsFile(path)
+        # Create path to constraints*.txt instead of versions*.cfg, etc.
+        filepath = buildout_file.path
+        filename = str(filepath)[len(str(filepath.parent)) + 1 :]
+        filename = filename.replace("versions", "constraints")
+        if "checkouts" in filename or "sources" in filename:
+            filename = (
+                filename.replace("checkouts", "mxcheckouts")
+                .replace("sources", "mxsources")
+                .replace(".cfg", ".ini")
+            )
+        else:
+            filename = filename.replace(".cfg", ".txt")
+        pip_path = filepath.parent / filename
+        if not pip_path.exists():
+            pip_path.write_text("")
+        buildout_file.to_pip(pip_path)
 
 
 class Manage:
@@ -322,6 +358,7 @@ def __call__(self, **kwargs):
                 get_package_version,
                 jenkins_report,
                 versions2constraints,
+                buildout2pip,
             ]
         )
         parser.dispatch()
diff --git a/plone/releaser/pip.py b/plone/releaser/pip.py
index 67baad0..d791fa9 100644
--- a/plone/releaser/pip.py
+++ b/plone/releaser/pip.py
@@ -1,6 +1,8 @@
 from .base import BaseFile
+from .base import Source
 from .utils import update_contents
 from collections import defaultdict
+from collections import OrderedDict
 from configparser import ConfigParser
 from functools import cached_property
 
@@ -135,9 +137,64 @@ def rewrite(self):
         self.path.write_text(new_contents)
 
 
-class IniFile(BaseFile):
+class MxSourcesFile(BaseFile):
     """Ini file for mxdev.
 
+    What we want to do here is similar to what we have in buildout.py
+    in the SourcesFile.
+    """
+
+    def __init__(self, file_location):
+        super().__init__(file_location)
+        self.config = ConfigParser(
+            default_section="settings",
+        )
+        # mxdev itself calls ConfigParser with extra option
+        # interpolation=ExtendedInterpolation().
+        # This turns a line like 'url = ${settings:plone}/package.git'
+        # into 'url = https://github.com/plone/package.git'.
+        # In our case we very much want the original line,
+        # especially when we do a rewrite of the file.
+        with self.path.open() as f:
+            self.config.read_file(f)
+
+    @cached_property
+    def data(self):
+        sources_dict = OrderedDict()
+        # I don't think we need to support [sources:marker].
+        for package in self.config.sections():
+            section = self.config[package]
+            sources_dict[package] = Source.create_from_section(section)
+        return sources_dict
+
+    @cached_property
+    def settings(self):
+        return self.config["settings"]
+
+    def __setitem__(self, package_name, enabled=True):
+        raise NotImplementedError
+
+    def rewrite(self):
+        """Rewrite the file based on the parsed data.
+
+        This will lose comments, and may change the order.
+        """
+        contents = ["[settings]"]
+        for key, value in self.settings.items():
+            contents.append(f"{key} = {value}")
+
+        for package in self:
+            contents.append("")
+            contents.append(self[package].to_section())
+
+        contents.append("")
+        new_contents = "\n".join(contents)
+        self.path.write_text(new_contents)
+
+
+class MxCheckoutsFile(BaseFile):
+    """Checkouts file for mxdev.
+
     What we want to do here is similar to what we have in buildout.py
     in the CheckoutsFile: remove a package from auto-checkouts.
     For mxdev: set 'use = false'.
@@ -159,7 +216,7 @@ def __init__(self, file_location):
             self.config.read_file(f)
         self.default_use = to_bool(self.config["settings"].get("default-use", True))
 
-    @property
+    @cached_property
     def data(self):
         checkouts = {}
         for package in self.config.sections():
@@ -168,7 +225,7 @@ def data(self):
                 checkouts[package] = True
         return checkouts
 
-    @property
+    @cached_property
     def sections(self):
         # If we want to use a package, we must first know that it exists.
         sections = {}
@@ -176,11 +233,28 @@ def sections(self):
             sections[package] = True
         return sections
 
+    @cached_property
+    def settings(self):
+        return self.config["settings"]
+
     @property
     def lowerkeys_section(self):
         # Map from lower case key to actual key in the sections.
         return {key.lower(): key for key in self.sections}
 
+    def append_package(self, package_name, enabled=True):
+        """Append a package to the checkouts.
+
+        The caller should have made sure this package is currently
+        not in the file.
+        """
+        contents = self.path.read_text()
+        if not contents.endswith("\n"):
+            contents += "\n"
+        use = "true" if enabled else "false"
+        contents += f"\n[{package_name}]\nuse = {use}\n"
+        self.path.write_text(contents)
+
     def __setitem__(self, package_name, enabled=True):
         """Enable or disable a checkout.
 
@@ -190,17 +264,15 @@ def __setitem__(self, package_name, enabled=True):
 
         But let's support the other way around as well:
         when default-use is true, we set 'use = false'.
-
-        Note that in our Buildout setup, we have sources.cfg separately.
-        In mxdev.ini the source definition and 'use = false/true' is combined.
-        So if the package we want to enable is not defined, meaning it has no
-        section, then we should fail loudly.
         """
         stored_package_name = self.lowerkeys_section.get(package_name.lower())
         if not stored_package_name:
-            raise KeyError(
-                f"{self.file_location}: There is no definition for {package_name}"
-            )
+            # Package is not known to us.
+            if self.default_use == enabled:
+                # The wanted state is the default state, so do nothing.
+                return
+            self.append_package(package_name, enabled=enabled)
+            return
         package_name = stored_package_name
         if package_name in self:
             use = to_bool(self.config[package_name].get("use", self.default_use))
@@ -263,19 +335,15 @@ def rewrite(self):
         """Rewrite the file based on the parsed data.
 
         This will lose comments, and may change the order.
-        TODO Can we trust self.config? It won't get updated if we change any data
-        after reading.
         """
         contents = ["[settings]"]
-        for key, value in self.config["settings"].items():
+        for key, value in self.settings.items():
             contents.append(f"{key} = {value}")
 
-        for package in self.sections:
+        for package in self.data:
             contents.append("")
             contents.append(f"[{package}]")
-            for key, value in self.config[package].items():
-                if self.config["settings"].get(key) != value:
-                    contents.append(f"{key} = {value}")
+            contents.append("use = true")
 
         contents.append("")
         new_contents = "\n".join(contents)
diff --git a/plone/releaser/release.py b/plone/releaser/release.py
index 2a92c2b..21c0715 100644
--- a/plone/releaser/release.py
+++ b/plone/releaser/release.py
@@ -3,7 +3,7 @@
 from plone.releaser.buildout import SourcesFile
 from plone.releaser.buildout import VersionsFile
 from plone.releaser.pip import ConstraintsFile
-from plone.releaser.pip import IniFile
+from plone.releaser.pip import MxSourcesFile
 from plone.releaser.pypi import can_user_release_package_to_pypi
 from zest.releaser import pypi
 from zest.releaser.utils import ask
@@ -311,5 +311,5 @@ def remove_from_checkouts(package_name):
         checkouts.remove(package_name)
     checkouts_file = coredev_dir / "mxdev.ini"
     if checkouts_file.exists():
-        checkouts = IniFile(checkouts_file)
+        checkouts = MxSourcesFile(checkouts_file)
         checkouts.remove(package_name)
diff --git a/plone/releaser/tests/input/mxcheckouts.ini b/plone/releaser/tests/input/mxcheckouts.ini
new file mode 100644
index 0000000..c7fbf35
--- /dev/null
+++ b/plone/releaser/tests/input/mxcheckouts.ini
@@ -0,0 +1,8 @@
+[settings]
+default-use = false
+
+[package]
+use = true
+
+[CamelCase]
+use = true
diff --git a/plone/releaser/tests/input/mxdev.ini b/plone/releaser/tests/input/mxsources.ini
similarity index 68%
rename from plone/releaser/tests/input/mxdev.ini
rename to plone/releaser/tests/input/mxsources.ini
index a0c15fd..f0e9dfd 100644
--- a/plone/releaser/tests/input/mxdev.ini
+++ b/plone/releaser/tests/input/mxsources.ini
@@ -1,16 +1,13 @@
 [settings]
 requirements-in = requirements.txt
 requirements-out = requirements-mxdev.txt
-contraints-out = constraints-mxdev.txt
-# The packages are defined, but not used by default.
-default-use = false
+constraints-out = constraints-mxdev.txt
 # custom variables
 plone = https://github.com/plone
 
 [package]
 url = ${settings:plone}/package.git
 branch = main
-use = true
 
 [unused]
 url = ${settings:plone}/package.git
@@ -19,4 +16,9 @@ branch = main
 [CamelCase]
 url = ${settings:plone}/CamelCase.git
 branch = main
-use = true
+
+[docs]
+url = ${setting:plone}/documentation.git
+branch = 6.0
+install-mode = skip
+target = extra/documentation
diff --git a/plone/releaser/tests/test_buildout.py b/plone/releaser/tests/test_buildout.py
index 95e28a2..977c33e 100644
--- a/plone/releaser/tests/test_buildout.py
+++ b/plone/releaser/tests/test_buildout.py
@@ -1,5 +1,4 @@
 from plone.releaser.buildout import CheckoutsFile
-from plone.releaser.buildout import Source
 from plone.releaser.buildout import SourcesFile
 from plone.releaser.buildout import VersionsFile
 
@@ -101,49 +100,6 @@ def test_checkouts_file_rewrite(tmp_path):
     )
 
 
-def test_source_standard():
-    src = Source.create_from_string(
-        "git https://github.com/plone/Plone.git pushurl=git@github.com:plone/Plone.git branch=6.0.x"
-    )
-    assert src.protocol == "git"
-    assert src.url == "https://github.com/plone/Plone.git"
-    assert src.pushurl == "git@github.com:plone/Plone.git"
-    assert src.branch == "6.0.x"
-    assert src.egg is True
-    assert src.path is None
-
-
-def test_source_not_enough_parameters():
-    with pytest.raises(IndexError):
-        Source.create_from_string("")
-    with pytest.raises(IndexError):
-        Source.create_from_string("git")
-
-
-def test_source_just_enough_parameters():
-    # protocol and url are enough
-    src = Source.create_from_string("git https://github.com/plone/Plone.git")
-    assert src.protocol == "git"
-    assert src.url == "https://github.com/plone/Plone.git"
-    assert src.pushurl is None
-    assert src.branch == "master"
-    assert src.egg is True
-    assert src.path is None
-
-
-def test_source_docs():
-    # Plone has a docs source with some extra options.
-    src = Source.create_from_string(
-        "git https://github.com/plone/documentation.git pushurl=git@github.com:plone/documentation.git egg=false branch=6.0 path=docs"
-    )
-    assert src.protocol == "git"
-    assert src.url == "https://github.com/plone/documentation.git"
-    assert src.pushurl == "git@github.com:plone/documentation.git"
-    assert src.branch == "6.0"
-    assert src.egg is False
-    assert src.path == "docs"
-
-
 def test_sources_file_data():
     sf = SourcesFile(SOURCES_FILE)
     assert sorted(sf.data.keys()) == ["Plone", "docs", "plone.alterego", "plone.base"]
diff --git a/plone/releaser/tests/test_buildout2pip.py b/plone/releaser/tests/test_buildout2pip.py
new file mode 100644
index 0000000..4d8b7ab
--- /dev/null
+++ b/plone/releaser/tests/test_buildout2pip.py
@@ -0,0 +1,115 @@
+from plone.releaser.manage import buildout2pip
+from plone.releaser.pip import ConstraintsFile
+
+import pathlib
+import shutil
+
+
+TESTS_DIR = pathlib.Path(__file__).parent
+INPUT_DIR = TESTS_DIR / "input"
+VERSIONS_FILE = INPUT_DIR / "versions.cfg"
+SOURCES_FILE = INPUT_DIR / "sources.cfg"
+CHECKOUTS_FILE = INPUT_DIR / "checkouts.cfg"
+
+
+def test_buildout2pip_one_path(tmp_path):
+    copy_path = tmp_path / "versions.cfg"
+    constraints_file = tmp_path / "constraints.txt"
+    shutil.copyfile(VERSIONS_FILE, copy_path)
+    assert not constraints_file.exists()
+    buildout2pip(path=copy_path)
+    assert constraints_file.exists()
+    cf = ConstraintsFile(constraints_file, with_markers=True)
+    assert cf.data == {
+        "CamelCase": "1.0",
+        "UPPERCASE": "1.0",
+        "annotated": "1.0",
+        "duplicate": "1.0",
+        "lowercase": "1.0",
+        "onepython": {'python_version == "3.12"': "2.1"},
+        "package": "1.0",
+        "pyspecific": {"": "1.0", 'python_version == "3.12"': "2.0"},
+    }
+    assert (
+        constraints_file.read_text()
+        == """-c https://zopefoundation.github.io/Zope/releases/5.8.3/constraints.txt
+annotated==1.0
+CamelCase==1.0
+duplicate==1.0
+lowercase==1.0
+package==1.0
+pyspecific==1.0
+pyspecific==2.0; python_version == "3.12"
+UPPERCASE==1.0
+onepython==2.1; python_version == "3.12"
+"""
+    )
+
+
+def test_buildout2pip_all(tmp_path):
+    versions_path = tmp_path / "versions.cfg"
+    constraints_file = tmp_path / "constraints.txt"
+    shutil.copyfile(VERSIONS_FILE, versions_path)
+    sources_path = tmp_path / "sources.cfg"
+    mxsources_file = tmp_path / "mxsources.ini"
+    shutil.copyfile(SOURCES_FILE, sources_path)
+    checkouts_path = tmp_path / "checkouts.cfg"
+    mxcheckouts_file = tmp_path / "mxcheckouts.ini"
+    shutil.copyfile(CHECKOUTS_FILE, checkouts_path)
+    buildout2pip(path=tmp_path)
+    assert constraints_file.exists()
+    assert mxsources_file.exists()
+    assert mxcheckouts_file.exists()
+    assert (
+        constraints_file.read_text()
+        == """-c https://zopefoundation.github.io/Zope/releases/5.8.3/constraints.txt
+annotated==1.0
+CamelCase==1.0
+duplicate==1.0
+lowercase==1.0
+package==1.0
+pyspecific==1.0
+pyspecific==2.0; python_version == "3.12"
+UPPERCASE==1.0
+onepython==2.1; python_version == "3.12"
+"""
+    )
+    assert (
+        mxsources_file.read_text()
+        == """[settings]
+docs-directory = documentation
+plone = https://github.com/plone
+plone_push = git@github.com:plone
+
+[docs]
+url = ${settings:plone}/documentation.git
+branch = 6.0
+install-mode = skip
+target = ${settings:docs-directory}
+
+[Plone]
+url = ${settings:plone}/Plone.git
+pushurl = ${settings:plone_push}/Plone.git
+branch = 6.0.x
+
+[plone.alterego]
+url = ${settings:plone}/plone.alterego.git
+branch = master
+
+[plone.base]
+url = ${settings:plone}/plone.base.git
+branch = main
+"""
+    )
+    assert (
+        mxcheckouts_file.read_text()
+        == """[settings]
+default-use = false
+
+[CamelCase]
+use = true
+
+[package]
+use = true
+"""
+    )
diff --git a/plone/releaser/tests/test_mxdev_checkouts.py b/plone/releaser/tests/test_mxdev_checkouts.py
new file mode 100644
index 0000000..f177bb0
--- /dev/null
+++ b/plone/releaser/tests/test_mxdev_checkouts.py
@@ -0,0 +1,118 @@
+from plone.releaser.pip import MxCheckoutsFile
+
+import pathlib
+import pytest
+import shutil
+
+
+TESTS_DIR = pathlib.Path(__file__).parent
+INPUT_DIR = TESTS_DIR / "input"
+MX_CHECKOUTS_FILE = INPUT_DIR / "mxcheckouts.ini"
+
+
+def test_mx_checkouts_file_data():
+    mf = MxCheckoutsFile(MX_CHECKOUTS_FILE)
+    # The data used to map lower case to actual case,
+    # but now actual case to True.
+    assert mf.data == {
+        "CamelCase": True,
+        "package": True,
+    }
+
+
+def test_mx_checkouts_file_contains():
+    mf = MxCheckoutsFile(MX_CHECKOUTS_FILE)
+    assert "package" in mf
+    assert "unused" not in mf
+    # We compare case insensitively.
+    assert "camelcase" in mf
+    assert "CamelCase" in mf
+    assert "CAMELCASE" in mf
+
+
+def test_mx_checkouts_file_get():
+    mf = MxCheckoutsFile(MX_CHECKOUTS_FILE)
+    assert mf["package"] is True
+    assert mf.get("package") is True
+    assert mf["camelcase"] is True
+    assert mf["CAMELCASE"] is True
+    assert mf["CamelCase"] is True
+    with pytest.raises(KeyError):
+        mf["unused"]
+    assert mf.get("unused") is None
+
+
+def test_mx_checkouts_file_add_known(tmp_path):
+    # When we add or remove a checkout, the file changes, so we work on a copy.
+    copy_path = tmp_path / "mxdev.ini"
+    shutil.copyfile(MX_CHECKOUTS_FILE, copy_path)
+    mf = MxCheckoutsFile(copy_path)
+    assert "unused" not in mf
+    mf.add("unused")
+    # Let's read it fresh, for good measure.
+    mf = MxCheckoutsFile(copy_path)
+    assert "unused" in mf
+    assert mf["unused"] is True
+
+
+def test_mx_checkouts_file_add_unknown(tmp_path):
+    # It actually does not matter for us if a package is unknown in a
+    # mxdev sources file: we are happy to add it in a mxdev checkouts file.
+    copy_path = tmp_path / "mxdev.ini"
+    shutil.copyfile(MX_CHECKOUTS_FILE, copy_path)
+    mf = MxCheckoutsFile(copy_path)
+    assert "unknown" not in mf
+    mf.add("unknown")
+    # Let's read it fresh, for good measure.
+    mf = MxCheckoutsFile(copy_path)
+    assert "unknown" in mf
+    assert mf["unknown"] is True
+
+
+def test_mx_checkouts_file_remove(tmp_path):
+    copy_path = tmp_path / "mxdev.ini"
+    shutil.copyfile(MX_CHECKOUTS_FILE, copy_path)
+    mf = MxCheckoutsFile(copy_path)
+    assert "package" in mf
+    mf.remove("package")
+    # Let's read it fresh, for good measure.
+    mf = MxCheckoutsFile(copy_path)
+    assert "package" not in mf
+    assert "CAMELCASE" in mf
+    mf.remove("CAMELCASE")
+    mf = MxCheckoutsFile(copy_path)
+    assert "CAMELCASE" not in mf
+    assert "CamelCase" not in mf
+    assert "camelcase" not in mf
+    # Check that we can re-enable a package:
+    # editing should not remove the entire section.
+    mf.add("package")
+    mf = MxCheckoutsFile(copy_path)
+    assert "package" in mf
+    # This should work for the last section as well.
+    mf.add("CamelCase")
+    mf = MxCheckoutsFile(copy_path)
+    assert "CamelCase" in mf
+
+
+def test_mx_checkouts_file_rewrite(tmp_path):
+    copy_path = tmp_path / "mxsources.ini"
+    shutil.copyfile(MX_CHECKOUTS_FILE, copy_path)
+    mf = MxCheckoutsFile(copy_path)
+    mf.rewrite()
+    # Read it fresh and compare
+    mf2 = MxCheckoutsFile(copy_path)
+    assert mf.data == mf2.data
+    # Check the entire text.
+    assert (
+        copy_path.read_text()
+        == """[settings]
+default-use = false
+
+[package]
+use = true
+
+[CamelCase]
+use = true
+"""
+    )
diff --git a/plone/releaser/tests/test_mxdev_sources.py b/plone/releaser/tests/test_mxdev_sources.py
new file mode 100644
index 0000000..18db59b
--- /dev/null
+++ b/plone/releaser/tests/test_mxdev_sources.py
@@ -0,0 +1,97 @@
+from plone.releaser.base import Source
+from plone.releaser.pip import MxSourcesFile
+
+import pathlib
+import pytest
+import shutil
+
+
+TESTS_DIR = pathlib.Path(__file__).parent
+INPUT_DIR = TESTS_DIR / "input"
+MX_SOURCES_FILE = INPUT_DIR / "mxsources.ini"
+
+
+def test_mx_sources_file_data():
+    mf = MxSourcesFile(MX_SOURCES_FILE)
+    assert list(mf.data.keys()) == ["package", "unused", "CamelCase", "docs"]
+    for key, value in mf.data.items():
+        assert isinstance(value, Source)
+
+
+def test_mx_sources_file_contains():
+    mf = MxSourcesFile(MX_SOURCES_FILE)
+    assert "package" in mf
+    assert "unused" in mf
+    # We compare case insensitively.
+    assert "camelcase" in mf
+    assert "CamelCase" in mf
+    assert "CAMELCASE" in mf
+
+
+def test_mx_sources_file_get():
+    mf = MxSourcesFile(MX_SOURCES_FILE)
+    package = mf["package"]
+    assert package
+    assert mf.get("package") == package
+    assert isinstance(package, Source)
+    assert package.protocol == "git"
+    assert package.url == "${settings:plone}/package.git"
+    assert package.branch == "main"
+    assert package.pushurl is None
+    assert package.path is None
+    assert package.egg is True
+    lowercase = mf["camelcase"]
+    uppercase = mf["CAMELCASE"]
+    camelcase = mf["CamelCase"]
+    assert lowercase
+    assert isinstance(lowercase, Source)
+    assert uppercase
+    assert camelcase
+    assert lowercase == uppercase
+    assert lowercase == camelcase
+    # The 'unused' package is not used (checked out), but we do not know that.
+    assert isinstance(mf.get("unused"), Source)
+    with pytest.raises(KeyError):
+        mf["no-such-package"]
+    docs = mf["docs"]
+    assert docs.branch == "6.0"
+    assert docs.egg is False
+    assert docs.path == "extra/documentation"
+
+
+def test_mx_sources_file_rewrite(tmp_path):
+    copy_path = tmp_path / "mxdev.ini"
+    shutil.copyfile(MX_SOURCES_FILE, copy_path)
+    mf = MxSourcesFile(copy_path)
+    mf.rewrite()
+    # Read it fresh and compare
+    mf2 = MxSourcesFile(copy_path)
+    assert mf.data == mf2.data
+    # Check the entire text.
+    assert (
+        copy_path.read_text()
+        == """[settings]
+requirements-in = requirements.txt
+requirements-out = requirements-mxdev.txt
+constraints-out = constraints-mxdev.txt
+plone = https://github.com/plone
+
+[package]
+url = ${settings:plone}/package.git
+branch = main
+
+[unused]
+url = ${settings:plone}/package.git
+branch = main
+
+[CamelCase]
+url = ${settings:plone}/CamelCase.git
+branch = main
+
+[docs]
+url = ${setting:plone}/documentation.git
+branch = 6.0
+install-mode = skip
+target = extra/documentation
+"""
+    )
diff --git a/plone/releaser/tests/test_pip.py b/plone/releaser/tests/test_pip.py
index 7386364..0c9cff4 100644
--- a/plone/releaser/tests/test_pip.py
+++ b/plone/releaser/tests/test_pip.py
@@ -1,5 +1,4 @@
 from plone.releaser.pip import ConstraintsFile
-from plone.releaser.pip import IniFile
 
 import pathlib
 import pytest
@@ -12,124 +11,6 @@
 CONSTRAINTS_FILE2 = INPUT_DIR / "constraints2.txt"
 CONSTRAINTS_FILE3 = INPUT_DIR / "constraints3.txt"
 CONSTRAINTS_FILE4 = INPUT_DIR / "constraints4.txt"
-MXDEV_FILE = INPUT_DIR / "mxdev.ini"
-
-
-def test_mxdev_file_data():
-    mf = IniFile(MXDEV_FILE)
-    # The data used to map lower case to actual case,
-    # but now actual case to True.
-    assert mf.data == {
-        "CamelCase": True,
-        "package": True,
-    }
-
-
-def test_mxdev_file_contains():
-    mf = IniFile(MXDEV_FILE)
-    assert "package" in mf
-    assert "unused" not in mf
-    # We compare case insensitively.
-    assert "camelcase" in mf
-    assert "CamelCase" in mf
-    assert "CAMELCASE" in mf
-
-
-def test_mxdev_file_get():
-    mf = IniFile(MXDEV_FILE)
-    assert mf["package"] is True
-    assert mf.get("package") is True
-    assert mf["camelcase"] is True
-    assert mf["CAMELCASE"] is True
-    assert mf["CamelCase"] is True
-    with pytest.raises(KeyError):
-        mf["unused"]
-    assert mf.get("unused") is None
-
-
-def test_mxdev_file_add_known(tmp_path):
-    # When we add or remove a checkout, the file changes, so we work on a copy.
-    copy_path = tmp_path / "mxdev.ini"
-    shutil.copyfile(MXDEV_FILE, copy_path)
-    mf = IniFile(copy_path)
-    assert "unused" not in mf
-    mf.add("unused")
-    # Let's read it fresh, for good measure.
-    mf = IniFile(copy_path)
-    assert "unused" in mf
-    assert mf["unused"] is True
-
-
-def test_mxdev_file_add_unknown(tmp_path):
-    # We cannot edit mxdev.ini to use a package when it is not defined.
-    copy_path = tmp_path / "mxdev.ini"
-    shutil.copyfile(MXDEV_FILE, copy_path)
-    mf = IniFile(copy_path)
-    assert "unknown" not in mf
-    with pytest.raises(KeyError):
-        mf.add("unknown")
-
-
-def test_mxdev_file_remove(tmp_path):
-    copy_path = tmp_path / "mxdev.ini"
-    shutil.copyfile(MXDEV_FILE, copy_path)
-    mf = IniFile(copy_path)
-    assert "package" in mf
-    mf.remove("package")
-    # Let's read it fresh, for good measure.
-    mf = IniFile(copy_path)
-    assert "package" not in mf
-    assert "CAMELCASE" in mf
-    mf.remove("CAMELCASE")
-    mf = IniFile(copy_path)
-    assert "CAMELCASE" not in mf
-    assert "CamelCase" not in mf
-    assert "camelcase" not in mf
-    # Check that we can re-enable a package:
-    # editing should not remove the entire section.
-    mf.add("package")
-    mf = IniFile(copy_path)
-    assert "package" in mf
-    # This should work for the last section as well.
-    mf.add("CamelCase")
-    mf = IniFile(copy_path)
-    assert "CamelCase" in mf
-
-
-def test_mxdev_file_rewrite(tmp_path):
-    copy_path = tmp_path / "mxdev.ini"
-    shutil.copyfile(MXDEV_FILE, copy_path)
-    mf = IniFile(copy_path)
-    mf.rewrite()
-    # Read it fresh and compare
-    mf2 = IniFile(copy_path)
-    assert mf.data == mf2.data
-    # Check the entire text.  Note that packages are alphabetically sorted.
-    # Currently we get the original case, but we may change this to lowercase.
-    assert (
-        copy_path.read_text()
-        == """[settings]
-requirements-in = requirements.txt
-requirements-out = requirements-mxdev.txt
-contraints-out = constraints-mxdev.txt
-default-use = false
-plone = https://github.com/plone
-
-[package]
-url = ${settings:plone}/package.git
-branch = main
-use = true
-
-[unused]
-url = ${settings:plone}/package.git
-branch = main
-
-[CamelCase]
-url = ${settings:plone}/CamelCase.git
-branch = main
-use = true
-"""
-    )
 
 
 def test_constraints_file_constraints():
diff --git a/plone/releaser/tests/test_source.py b/plone/releaser/tests/test_source.py
new file mode 100644
index 0000000..6221674
--- /dev/null
+++ b/plone/releaser/tests/test_source.py
@@ -0,0 +1,84 @@
+from configparser import ConfigParser
+from plone.releaser.buildout import Source
+
+import pytest
+
+
+def test_source_standard():
+    src = Source.create_from_string(
+        "Plone",
+        "git https://github.com/plone/Plone.git pushurl=git@github.com:plone/Plone.git branch=6.0.x",
+    )
+    assert src.name == "Plone"
+    assert src.protocol == "git"
+    assert src.url == "https://github.com/plone/Plone.git"
+    assert src.pushurl == "git@github.com:plone/Plone.git"
+    assert src.branch == "6.0.x"
+    assert src.egg is True
+    assert src.path is None
+
+
+def test_source_not_enough_parameters():
+    with pytest.raises(IndexError):
+        Source.create_from_string("package", "")
+    with pytest.raises(IndexError):
+        Source.create_from_string("package", "git")
+
+
+def test_source_just_enough_parameters():
+    # protocol and url are enough
+    src = Source.create_from_string("Plone", "git https://github.com/plone/Plone.git")
+    assert src.name == "Plone"
+    assert src.protocol == "git"
+    assert src.url == "https://github.com/plone/Plone.git"
+    assert src.pushurl is None
+    assert src.branch == "master"
+    assert src.egg is True
+    assert src.path is None
+
+
+def test_source_docs():
+    # Plone has a docs source with some extra options.
+    src = Source.create_from_string(
+        "docs",
+        "git https://github.com/plone/documentation.git pushurl=git@github.com:plone/documentation.git egg=false branch=6.0 path=docs",
+    )
+    assert src.name == "docs"
+    assert src.protocol == "git"
+    assert src.url == "https://github.com/plone/documentation.git"
+    assert src.pushurl == "git@github.com:plone/documentation.git"
+    assert src.branch == "6.0"
+    assert src.egg is False
+    assert src.path == "docs"
+
+
+def test_source_from_section():
+    config = ConfigParser()
+    config.read_string("[Plone]\nurl = blah")
+    src = Source.create_from_section(config["Plone"])
+    assert src.name == "Plone"
+    assert src.url == "blah"
+    assert not src.pushurl
+    assert src.branch == "main"
+    assert src.egg
+    assert not src.path
+
+    config.read_string(
+        "\n".join(
+            [
+                "[package]",
+                "url = hop",
+                "pushurl = other",
+                "branch = 1.x",
+                "install-mode=skip",
+                "target = /some/path",
+            ]
+        )
+    )
+    src = Source.create_from_section(config["package"])
+    assert src.name == "package"
+    assert src.url == "hop"
+    assert src.pushurl == "other"
+    assert src.branch == "1.x"
+    assert not src.egg
+    assert src.path == "/some/path"
diff --git a/plone/releaser/tests/test_versions2constraints.py b/plone/releaser/tests/test_versions2constraints.py
index 42dc77c..2cf96a6 100644
--- a/plone/releaser/tests/test_versions2constraints.py
+++ b/plone/releaser/tests/test_versions2constraints.py
@@ -2,7 +2,6 @@
 from plone.releaser.pip import ConstraintsFile
 
 import pathlib
-import pytest
 import shutil
 
 
@@ -14,8 +13,7 @@
 VERSIONS_FILE4 = INPUT_DIR / "versions4.cfg"
 
 
-@pytest.mark.current
-def test_versions2constraints(tmp_path):
+def test_versions2constraints_one_path(tmp_path):
     copy_path = tmp_path / "versions.cfg"
     constraints_file = tmp_path / "constraints.txt"
     shutil.copyfile(VERSIONS_FILE, copy_path)
@@ -23,7 +21,16 @@ def test_versions2constraints(tmp_path):
     versions2constraints(path=copy_path)
     assert constraints_file.exists()
     cf = ConstraintsFile(constraints_file, with_markers=True)
-    print(cf.data)
+    assert cf.data == {
+        "CamelCase": "1.0",
+        "UPPERCASE": "1.0",
+        "annotated": "1.0",
+        "duplicate": "1.0",
+        "lowercase": "1.0",
+        "onepython": {'python_version == "3.12"': "2.1"},
+        "package": "1.0",
+        "pyspecific": {"": "1.0", 'python_version == "3.12"': "2.0"},
+    }
     assert (
         constraints_file.read_text()
         == """-c https://zopefoundation.github.io/Zope/releases/5.8.3/constraints.txt
@@ -38,3 +45,87 @@ def test_versions2constraints(tmp_path):
 onepython==2.1; python_version == "3.12"
 """
     )
+
+
+def test_versions2constraints_all(tmp_path):
+    versions_path = tmp_path / "versions.cfg"
+    versions2_path = tmp_path / "versions2.cfg"
+    versions3_path = tmp_path / "versions3.cfg"
+    versions4_path = tmp_path / "versions4.cfg"
+    constraints_file = tmp_path / "constraints.txt"
+    constraints2_file = tmp_path / "constraints2.txt"
+    constraints3_file = tmp_path / "constraints3.txt"
+    constraints4_file = tmp_path / "constraints4.txt"
+    shutil.copyfile(VERSIONS_FILE, versions_path)
+    shutil.copyfile(VERSIONS_FILE2, versions2_path)
+    shutil.copyfile(VERSIONS_FILE3, versions3_path)
+    shutil.copyfile(VERSIONS_FILE4, versions4_path)
+    assert not constraints_file.exists()
+    assert not constraints2_file.exists()
+    assert not constraints3_file.exists()
+    assert not constraints4_file.exists()
+    versions2constraints(path=tmp_path)
+    assert constraints_file.exists()
+    assert constraints2_file.exists()
+    assert constraints3_file.exists()
+    assert constraints4_file.exists()
+    cf = ConstraintsFile(constraints_file, with_markers=True)
+    assert cf.data == {
+        "CamelCase": "1.0",
+        "UPPERCASE": "1.0",
+        "annotated": "1.0",
+        "duplicate": "1.0",
+        "lowercase": "1.0",
+        "onepython": {'python_version == "3.12"': "2.1"},
+        "package": "1.0",
+        "pyspecific": {"": "1.0", 'python_version == "3.12"': "2.0"},
+    }
+    assert (
+        constraints_file.read_text()
+        == """-c https://zopefoundation.github.io/Zope/releases/5.8.3/constraints.txt
+annotated==1.0
+CamelCase==1.0
+duplicate==1.0
+lowercase==1.0
+package==1.0
+pyspecific==1.0
+pyspecific==2.0; python_version == "3.12"
+UPPERCASE==1.0
+onepython==2.1; python_version == "3.12"
+"""
+    )
+    cf2 = ConstraintsFile(constraints2_file, with_markers=True)
+    assert cf2.data == {
+        "one": "1.1",
+        "three": {'python_version == "3.12"': "3.2"},
+        "two": "2.0",
+    }
+    assert (
+        constraints2_file.read_text()
+        == """-c constraints3.txt
+one==1.1
+two==2.0
+three==3.2; python_version == "3.12"
+"""
+    )
+    cf3 = ConstraintsFile(constraints3_file, with_markers=True)
+    assert cf3.data == {
+        "one": "1.0",
+        "three": {"": "3.0", 'python_version == "3.12"': "3.1"},
+    }
+    assert (
+        constraints3_file.read_text()
+        == """-c constraints4.txt
+one==1.0
+three==3.0
+three==3.1; python_version == "3.12"
+"""
+    )
+    cf4 = ConstraintsFile(constraints4_file, with_markers=True)
+    assert cf4.data == {"four": "4.0", "five": {'platform_system == "Darwin"': "5.0"}}
+    assert (
+        constraints4_file.read_text()
+        == """four==4.0
+five==5.0; platform_system == "Darwin"
+"""
+    )
diff --git a/setup.py b/setup.py
index 35a725e..2c98ce3 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup
 
 
-version = "2.2.3.dev0"
+version = "2.3.0.dev0"
 
 long_description = "{}\n{}".format(
     open("README.rst").read(), open("CHANGES.rst").read()