I replaced mythtv with tvheadend on the backend and kodi on the frontend like 5 or 6 years ago.
The setup and configuration at the time on mythtv was slanted towards old ( obsolete ) analog tuners and static setup and tvheadend was like a breath of fresh air in comparison where you could point it at a DVB mux or two and it would mostly do what you want without having to fight it.
I’m not sure how much longer I’ll want something that can tune DVB-S2 and DVB-T though. Jellyfin and friends handle everything other than legacy TV better than kodi these days.
It’s an engineering sample that was produced before the final product was available. They use the really early ones to figure out if what they got back from the fab actually runs and how fast it will go safely. Later ones end up at motherboard partners so they can test their new board designs.
It is pretty common for them to leak out onto the second hand market after the final release. I’ve never heard of one that had any real problems, but in theory you might be buying something that has some issue that they hadn’t discovered at that point.