I think Sourcehut is the more portable of Git forges. Everything is stored in standard formats, its workflow isn't anything bespoke but just a good automation for git send-email, and I believe the source code should be all published.

In my eyes, if this ever does become a problem, migrating elsewhere wouldn't be that much trouble. When the "cryptocurrency purge" happened, maintainers were given 2 months of advance notice, which is a little short but reasonable.

[0] https://sourcehut.org/blog/2022-10-31-tos-update-cryptocurre...