Today I learned that mirroring git repositories can help license enforcement. In legal cases a mirrored repository that the original authors have no access to, can help to proof that their git history is unchanged and can be used as evidence in the case, since the mirrored repository attests the authenticity of the original/upstream one.

I came across this while listening to this talk from FOSDEM 2021 about an AGPL case in Italy and as someone running an own mirror repository setup on SI-GitLab, this just reinforces my motivation towards mirroring important projects.