I would like to nominate Jakob for +2 in mediawiki/ repositories.
Code reviews: https://gerrit.wikimedia.org/r/#/q/reviewedby:%22Jakob+%253Cjakob.warkotsch%2540wikimedia.de%253E%22
Merged patches: https://gerrit.wikimedia.org/r/#/q/owner:%22Jakob%22+status:merged
Jakob has been working with mediawiki for some years. He has worked on features and extensions such as Wikibase, WikibaseLexeme and RevisionSlider. I have no doubts.