Seems we have no more blockers for <maplink> tag on all Wikipedias. We will enable it tomorrow, Sept 1st. <maplink> tag allows editors to add a link to a popup map, complete with extra geojson overlay data.
See help page for instructions: https://www.mediawiki.org/wiki/Help:Extension:Kartographer#.3Cmaplink.3E
Submit bugs to phabricator: https://phabricator.wikimedia.org/maniphest/task/edit/form/1/?tags=Kartograp...