But is it open? Seems not; parts are closed so is that not just more of the same?

postmarketOS, Mobian, PureOS are open.

Yeah, some bits (parts of the GUI & some of the default apps) are still closed.

But I think there is a good chance they will finally open those now - never really made any sense to keep them closed and preventing the community from contributing. Rumors had it it was due to non-cooperative investors.

Not Jolla is finally independent again, so at least in theory they can finally do the right thing. :)