I see potential in having such a place for the community.
I see your point and a while ago I also mentioned how Csound has a FLOSS Manual that doesn't conflict to what they call 'the canonical manual'. Something like that can happen and that's what actually happened back then (and I was part of it as one of the contributors. Now, that looks good in theory. In practice, I don't believe in it so much, hence, the FLOSS Manual has been abandoned now for so many years, none of the original authors were there to keep it alive (me included), I spoke to Derek (one of the main forces behind this, who doesn't follow the list anymore) and he had no login or will to get back on this (he considered 'timed served' and I agree and thank him for his services).
Anyway, where I'm getting at is that we might not pull it off... I brought this up in may here, also into the Pd Forum and on the facebook group, nothing happened. It stayed in my to do list until I finally tried getting access...
And I, for one, am much more concerned now in helping with Pd's manual. I wrote a new section on managing externals, for instance. Others have contributed nicely to it. I guess we can start and focus, as a community, to help with Pd's documentation first, before envisioning such ambitious side/complementary projects.
This is why I'm just hoping to change the title of this FLOSS Manuals to 'Pd-extended', put a remark on its introduction that it is a historical document, and leave it at that.
If people want to still join forces and work on a new one from scratch, great. I can see if I can also join in, awesome, but that's something else.