How to set up Peer-to-Peer collaboration with Git?

Question

Because for technical and legal reason the usage of a central repository is for some projects not possible, I would like to set up the versioning with Git in a peer to peer fashion without a catalyzing server. How could this be done?

Answer 1

This would mean sending patches, through for instance email.

See "Git Tip of the Week: Patches by Email"

One way of getting changes is by providing a patch, or a set of changes which can be applied to a remote repository at the other end.

Git started life as a distributed version control system for the Linux project, which actively uses mail lists both as a discussion mechanism and also as a distribution mechanism for patches (changes) for an existing codebase. (New features are just a special case of patching nothing to add the new code.)

Another option is to email a git bundle, which can be incremental.
It is one file, and you can fetch from it.

It is different from a patch.

Answer 2

git daemon might be what you are looking for.

Beware that this mechanism exposes your project to the network as it does not have authentication mechanism.

https://git-scm.com/book/en/v2/Git-on-the-Server-Git-Daemon