Change Details

However, core does (they show up in WhatLinksHere, and it's the entire basis for features like [Special:WantedPages](https://en.wikipedia.org/wiki/Special:WantedPages)). Reported by @He7d3r at T59512. See for example http://ee-flow.wmflabs.org/wiki/Special:WhatLinksHere/Test1234 and http://ee-flow.wmflabs.org/w/index.php?title=Topic:Sepea8m6b6e46u80&topic_showPostId=sfi6980u5bqsy3k0#flow-post-sfi6980u5bqsy3k0 . Cause is a check in ReferenceFactory, along with various `Title` parameters that should allow null (`Title $foo = null`).