https://gerrit.wikimedia.org/r/#/q/status:open+project:mediawiki/extensions/BookManagerv2,n,z contains 21 open patches waiting for review since Google Summer of Code 2014. If they are good, it would be great if someone could merge them. If they are not good enough, then please mark them with -1. If there is another problem, please share it so we can find a solution.
I'm creating this task to see if this helps bringing more attention to this problem, reported already at T17071#1384929. Today, this repository is the second slowest in terms of code review according to http://korma.wmflabs.org/browser/gerrit_review_queue.html
Maybe a code review sprint can be organized in the context of the Wikisource Conference?