diff --git a/src/doc/style-guide/src/README.md b/src/doc/style-guide/src/README.md
index 49a4bce2f5dcd..3d47e33841a54 100644
--- a/src/doc/style-guide/src/README.md
+++ b/src/doc/style-guide/src/README.md
@@ -49,6 +49,27 @@ a_function_call(foo,
 This makes for smaller diffs (e.g., if `a_function_call` is renamed in the above
 example) and less rightward drift.
 
+### Trailing commas
+
+Lists should have a trailing comma when followed by a newline:
+
+```rust
+function_call(
+    argument,
+    another_argument,
+);
+
+let array = [
+    element,
+    another_element,
+    yet_another_element,
+];
+```
+
+This makes moving code (e.g., by copy and paste) easier, and makes diffs
+smaller, as appending or removing items does not require modifying another line
+to add or remove a comma.
+
 ### Blank lines
 
 Separate items and statements by either zero or one blank lines (i.e., one or
diff --git a/src/doc/style-guide/src/principles.md b/src/doc/style-guide/src/principles.md
index c3104e6d9b60f..c86121e6a4697 100644
--- a/src/doc/style-guide/src/principles.md
+++ b/src/doc/style-guide/src/principles.md
@@ -27,10 +27,3 @@ following principles (in rough priority order):
     - ease of implementation (in Rustfmt, and in other tools/editors/code generators)
     - internal consistency
     - simplicity of formatting rules
-
-
-## Overarching guidelines
-
-Lists should have a trailing comma when followed by a newline, see the block
-indent example above. This choice makes moving code (e.g., by copy and paste)
-easier and makes smaller diffs.