Auto refresh can be disabled globally or per-snap now, the server is still closed source.
I'm not sure why there's no real FOSS alternative to it, but there was an attempt at one point. I've always thought it would be cool to make a torrent-based P2P snap store.
No it isn't. Canonical's snap store is closed source but Snap does not depend on it and the process of configuring snapd to fetch and install from your own store is fully documented and needs no proprietary or Canonical tech whatsoever.
I found this... Not really "Canonical docs", no clear way to support multiple architectures, and it hasn't been updated in a couple years, but I guess it works...
