<maplink> and <mapframe> tags show maps in fullscreen or embedded page mode. In Wikivoyage mode (at least) in the html document head a JavaScript object is embedded in mw.config.set() named wgKartographerLiveData. It is created when <maplink> and <mapframe> tags are used.

In case of a missing <mapframe> tag, ie only <maplink> tags are used, all the wgKartographerLiveData arrays are empty ([]). Therefore it is impossible to add a map with JavaScript later because of missing data.