I would be quite happy to see also the beta releases tagged in Github. Currently, only the "stable" releases are getting tags and thus it is for example not possible to build docker containers from a specific beta version using the official build scripts, and not going directly to trunk.

I consider beta releases to be a bit more stable than trunk. I suppose trunk receives no quality assurance at all, so might be completely broken, but beta releases have some kind of pre-checking. I have several small Zabbix'es which I would use to test betas, but not possible to build containers without quite some effort.