That does not seem particularly unusual to me? This is a piece of formerly proprietary software, that is now being made open source. So of course almost all co

That does not seem particularly unusual to me? This is a piece of formerly proprietary software, that is now being made open source. So of course almost all contributors would be employees of the former owner of the proprietary version of the software. Just like for example Doom was still 100% made by id software, at the moment of it becoming open source. How this evolves/develops remains to be seen, of course. But as of right now, I'd say that's to be expected.