My understanding is that admins would be able to access it. I’m not sure if this means any admin, or just the ones of the sender and recipient.

I manage a (relatively small) gitea instance, the software that forgejo was recently hard forked from. The maintenance is incredibly simple, really no problem if you’ve ever run any sort of publicly facing web service.

In this case I meant the one packaged by your distro.

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I would use the native version. For something like this, it makes sense that it should have less restricted/sandboxed access to the underlying system.