Hello,
The Discovery Search team would like to run a few A/B tests on this project; each test will last about a week. A small subsection of users would see these tests. These tests would help us determine if adding extra search results across wiki projects in the same language is useful, relevant, and are of interest to users.
If there are concerns or questions, please share them and the team will respond. If no significant problems are identified, we would like start the tests in late December 2016 or January 2017.
More details at mw:Cross-wiki Search Result Improvements. We have described the initial tests that we want to run at mw:Cross-wiki Search Result Improvements/Testing