For continous integration purposes, I have pooled a Jenkins slave running Jessie and applied the puppet class role::ci::slave::labs which brings the MediaWiki packages defined in Mediawiki::Packages puppet class and others.
There are lot of packages missing, would be nice to start doing the grunt work of backporting them from unstable, verify whether they are still needed or use a different version. Might be appropriate to fill sub tasks as needed.
My instance is integration-slave-jessie-1001.eqiad.wmflabs.
|ffmpeg||PTS Missing from jessie though in testing. More details on lwn.net. Forked to libav which Debian has chosen||https://gerrit.wikimedia.org/r/222999|
|libvips15||PTS Jessie has libvips38||T103322|
|libmemcached10||PTS Jessie has libmemcached11||T103315|
A bunch of fonts virtual packages. They are in Debian but for some reason cant be installed, that spurts out the list of packages to install instead :(
Debian has some meta packages such as fonts-indic.
There will be probably much more missing since puppet skips installing other packages due to missing dependencies.