I’ve been testing the mirroring setup from SourceHut to GitHub, and it seems easy enough to set up. On the GitHub side, fine grained access tokens allow modifications to the mirrored repositories, and on the SourceHut side, the tokens are made available to the build pipelines for each repo to be mirrored.
One interesting feature of SourceHut is the integration of mailing lists, git repos, and the CI system. The SourceHut build system will automatically build patches sent to a mailing list which refer to a git repo in the same SourceHut project. To avoid misuse, the build system is only available to paying users, and patches are built with the author’s permissions, not the permission of the owner of the target repo. If a patch submitter does not have a paid plan, SourceHut will not build the patch. And even more important: Patches are built without access to the receiver’s tokens.