Libgit2 fails on non-commit refs that are not in refs/tags/ (see libgit2/libgit2#3595). As a temporary workaround, git-backup only fetches branches (refs/heads/) and tags (refs/tags/).

• Check for extra refs and warn?
• Docker image
• Package backups in bundles (no pygit, call git)
• Add snippets
• Add wikis
• Separate pylint and mypy from pytest. See https://jichu4n.com/posts/how-to-add-custom-build-steps-and-commands-to-setuppy/ https://github.com/cmccully/astropy/blob/d67ca3681a5cef69feada74540db1a9c7b177b65/astropy/tests/command.py