User blog comment:Kirkburn/Technical Update: December 2, 2015/@comment-5558012-20151202212702/@comment-24473195-20151203063543

@Saftzie:

"Maybe if Wikia removes the ability to use u: in importArticles, although there are fallbacks to importArticles."

Those fallbacks wouldn't work because:

1. Wikia doesn't allow saving .js pages to the main namespace in any other wiki.

2. In the event that someone does save it somehow and tries to use ajax, the JS reviewer can simply reject scripts that use such fallbacks. In fact this could be automatically rejected by a bot that looks for jquery ajax calls instead of mediawiki's native ones.

Anyway, none of the JS changes go live immediately, so that's yet another layer of protection against bad practices.