Looking at the README in https://salsa.debian.org/mirror-team/archvsync I saw no instructions on how to contribute, nor any indication of where bugs are welcome. It would be nice to tell users that found an issue that they can file bugs in the Debian BTS and that they can submit merge requests for patches (or that they can send patch to the BTS if that's your preference). IMO it would make sense to allow GitLab issues on the project too for "upstream change", but YMMV.