Suppressed username in file history is leaked in case of file transclusion using InstantCommons / $wgForeignFileRepos
The username of the first file revision in this testcase is shown on the foreign wiki:
http://commons.wikimedia.org/wiki/File:Example_file_for_a_RevDel_bug.jpg
http://de.wikipedia.org/wiki/Datei:Example_file_for_a_RevDel_bug.jpg
Version: 1.17.x
Severity: major