@Nemo_bis, please don't change the priority set by the maintainers, unless you plan to take the task and work on it. Explaining why you think this task should have a higher priority (as you are also doing) is correct, of course. My comment is only about the back and forth changing priorities, and is in line with https://www.mediawiki.org/wiki/Phabricator/Project_management#Setting_task_priorities
MediaWiki's policy is to respect the users' GENDER preferences, whatever individual developers might think about it. This bug is high priority even if MobileFrontend is so abandoned as to not be able to provide basic MediaWiki support; in that case, it suffices to know and other people will start caring for the abandoned extension, as always happens.