Each title ( in any projet and in any language ) with datas in wikibase can give its item.id to any module.
Probably across mw.title.new().itemid
If we give to modules the wikibase item.id linked to the title:
* The module writer have not to search it.
* That is made only once for each title.
* The expensive function to find it is no more needed.
* The item.id become a part of the title and is easy to get.