Since I posted an issue comment two weeks ago I talked with the other Librem 5 team members about the issue and started a discussion about what should be done. I outlined all the potential options, but there wasn’t a consensus about what to do.
It was suggested that project already using the public Zanata server (Phosh and Chats) could continue using it, whereas other projects (Calls) could start using GNOME’s translation infrastructure (see this issue) as that project may well end up upstream in its entirety.
I think existing projects could be switched to the GNOME infrastructure and translated there – it just needs someone from those projects to take the lead. There are issues with downstream forks, but I think they could be dealt with later. Migration doesn’t have to be done all at once.
Nobody is driving this effort forward at the moment. I was only involved because thing kind of thing has traditionally fallen to the person doing the documentation.