As a team, and based on feedback generated on MediaWiki and the talk page, we want to create methods and functionality to generate and display additional (and relevant) search results on Wikipedia that are from other sister projects and the native language wiki where the user entered their search query.
Our goal in this effort is to add this functionality onto Wikipedia and gather results from other projects to display on the search results page. These search results will be in the same language as the search was done in - i.e.: if I search on en.wiki for what is the history of the olympics I want to see search results in English on en.wiki and also relevant results (in English) from sister projects such as wikiquote, wiktionary, wikivoyage, etc.
We've discussed this in various different meetings, here are the etherpad notes that contain the raw minutes from those meetings, in order to refresh our memories (listed in no particular order):
This ticket is to cover the backend functionality that we need to build to support the front end display (T145917)