Hi!
I've been working for a while now on splitting the code that does searching - and more specifically, searching using ElasticSearch/CirrusSearch - out from Wikibase extension code and into a separate extension (see https://phabricator.wikimedia.org/T190022). If you don't know what I'm talking about here (or not interested in this topic), you can safely skip the rest of this message.
The extension WikibaseCirrusSearch is meant to have all the code related to ElasticSearch and CirrusSearch extension integration to Wikibase, so main Wikibase repo does not have any Elastic-specific code. This means that if you have your own Wikibase install, you'll need (after migration is done) to install WikibaseCirrusSearch to get search functionality like we have on Wikidata now. There will also be change in configurations - I'll make a migration document and announce it separately. We're now working on deploying and testing it on Beta/testwiki, after which we'll start migrating production to running the code in this extension for search, after which the search code in the Wikibase repo itself will be removed. You can track the progress in the Phabricator task mentioned above.
Since code migration is in pretty advanced stage now, I'd like to ask if you make any changes to any code under repo/includes/Search or repo/config in Wikibase repo, or any tests or configs related to those, please inform me (by adding me to patch reviewers/CC or by email or by any other reasonable means) so that these changes won't be lost in the migration. I'll be looking into the latest patches for anything related periodically, but I might miss things.
WikibaseLexeme code that relates to search will be also migrated to a separate extension (WikibaseLexemeCirrusSearch), that work will be starting soon. So the request above applies to the search parts of the WikibaseLexeme code also.
If you have any questions/comments, please feel free to ask me, on the lists or on the IRC.
Thanks,