Interesting to note that this specifically says several times that it's free, but it doesn't appear to be open source, and the only availability seems to be an OVA [1] file.

Have I missed something, or is this a non-open free-as-in-beer tool?

I'm not saying that's necessarily a bad thing - I absolutely support the goal of companies/teams/groups having more control through better self-hostable tools (and any change that might have on the current mindshare-monopoly GitHub has)

[1] https://en.wikipedia.org/wiki/Open_Virtualization_Format