Last modified: 2014-06-17 17:02:57 UTC
footerCleanup.js directly assigns to window.onload. This is deprecated. Among other things, it will clobber another registration done the same way.
https://bugzilla.wikimedia.org/45976
Sorry, I meant to link the Gerrit change, https://gerrit.wikimedia.org/r/#/c/53419/