It's "smart" EAV[0] Database schema gave my colleagues so much good time. I do not know how it became in more recent versions, but at the time I distinctly remember them dealing with abysmal DB performances and completely gibberish auto-generated queries.
In one case, I had to manually dig through the DB and write an ad-hoc query to extract data that was needed for reporting, otherwise the software would start doing a gazillion of round trips between a DB lookup, an AS-level computation, another DB lookup...
That DB design tasted of super-mega-premature optimization, in which the developers wanted to guarantee extensibility at all costs, foregoing in the process the design of an actual data model.
[0] https://en.wikipedia.org/wiki/Entity%E2%80%93attribute%E2%80...