Revert r88008 (add size difference to Special:Contributions) and its large group of friends, they break Special:Contributions by joining against recentchanges and dropping any contribs that have fallen off RC. See also CR discussion at r95496, which was Sam's incomplete attempt at reverting this.
Follow-ups reverted: r88019, r88024, r88111, r88117, r88252, r96081. Left the parts of r88025 and r88026 (everything except the MessagesEn.php change) that disable the namespace filter in miser mode intact; that was a good change and not really related to the r88008 other than that it touched nearby code.