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Why does the commit editor hide the coauthored message? Why not pre-populate the text field and users take or leave it when committing?
Co-Authored-By is normally a trailer, and trailers aren’t part of the commit message. It’s likely the commit editor isn’t set up to show trailers. They’re not exactly obscure, but it does seem that they’re relatively unknown.
The docs for the function to interpret trailers even says this explicitly: https://git-scm.com/docs/git-interpret-trailers
> Add or parse structured information in commit messages