Andre won't tell you, but he wrote this:
http://blogs.gnome.org/aklapper/2014/12/17/welcome-phabricator/
The best in-depth analysis of a Bugzilla to Phabricator migration available
in the Internet. Not that there is much competition... I'm sure it will be
useful to someone, especially in conjunction with Chase's migration script
and the detailed logs and tasks archived.
--
Quim Gil
Engineering Community Manager @ Wikimedia Foundation
http://www.mediawiki.org/wiki/User:Qgil