I'm not sure right off if/where documented,
so I'll reply from memory (I know, that's always dangerous :) but am sure
Bjorn or Mike will correct me if I am misremembering.
I believe the rule is that incubating
projects can release without graduating as long as they go through a release
A release review in this case means,
basically, they have release quality IP records and clearance, but not
other attributes of released projects
(community, quality, APIs, predictability, etc).
Eighty does sound like a lot, but ..
those are the rules we established for Ganymede (i.e. that incubating projects
could be part of Ganymede as long as they went
through a release review) ... so ...
we may want to re-think that for Io? Or ... maybe add a feature in P2 update
that says "show/hide incubating features" :)