In the MobileFrontend extension for MediaWiki, XSS exists within the edit summary field of the watchlist feed. This affects REL1_31, REL1_32, and REL1_33.
In the MobileFrontend extension 1.31 through 1.33 for MediaWiki, XSS exists within the edit summary field in includes/specials/MobileSpecialPageFeed.php.