This is a server that takes a GOPROXY url as an argument and gives you a UI documentation similar to godoc.org except all data comes from the GOPROXY and not from VCS.
If your GOPROXY supports a /catalog endpoint, then you can see and search the list of existing modules on the home page.
~ GO111MODULE=on go install marwan.io/moddoc
# Assuming you have a GOPROXY server running at http://localhost:3000
~ GOPROXY=http://localhost:3000 moddoc
Visit http://localhost:3001
You can also visit http://localhost:3001/<module>/@v/<version>
to see a documentation package directly.
For example, http://localhost:3001/github.com/pkg/errors/@v/v0.8.1
This program was meant as a temporary workaround until the Go team launched their own Module aware doc website. Now that they have, please feel free to use the more fully featured https://pkg.go.dev