Chad seems to think that the TitleKey extension is no longer needed on Wikimedia wikis due to the MWSearch extension being installed.
If this is true, removing the extension from the Wikimedia conf files and updating the branch-making script would be nice to do.
Version: wmf-deployment
Severity: enhancement
Bit of IRC that led to this bug:
<^d> Why do we still have the TitleKey extension installed?
<Elsie> ikr
<Elsie> ^d: You mean it shouldn't be installed or it should be in core?
<Elsie> I favor putting it in core.
<^d> Elsie: I don't know why we install it at WMF.
<Elsie> Isn't it used for search suggestions?
<^d> Both TitleKey and MWSearch's implementation's return false, which means whichever one that is registered first will end up halting execution of further hooks.
- Elsie shrugs.
<^d> MWSearch wins because it registers first.
<^d> There's not much of a point of having multiple suggestion sources anyway. I can see why it was probably useful, but it hasn't been for a long time afaict.
<^d> At least not at wmf. It may be useful for core or for bundling by default.
TitleKey was removed from Wikimedia's extension-list file in https://gerrit.wikimedia.org/r/#/c/185450/.