[Dev] history of ZODB use/problems/removal?

[Bill Seitz]

Are there any references online (wiki pages, list archives) discussing 
the decision to eliminate ZODB, and a short explanation of what's being 
used instead? (Or maybe there are multiple non-ZODB back-ends possible, 
all hidden behind RAP...)

I guess I'm just curious in terms of lessons learned for other 
situations calling for a persistence engine...

(I've tried searching various places and couldn't find anything that 
seemed directly relevant...)