"'" Conveniently #git can create a single-file archive of a repository via 'git bundle create' which appears to be the perfect fit for backups. […] I noticed that a small but fixed subset of repositories are getting backed up despite having no changes made. […] Turns out that for some repositories bundling is nondeterministic. […] What caught my eye was Delta compression using up to 8 threads—parallelism is a classic source of inherent nondeterminism. […]"

https://baecher.dev/stdout/reproducible-git-bundles/