User blog comment:Kirkburn/Technical Update: October 26, 2015/@comment-24757753-20151027085907

> ''Text labels in Facebook widgets/plugins will be localized according to a user's language preference (or the community's content language, for those not logged in). Note: this is the second implementation of this change, as the first caused problems.''

This implementation causes problems too (testing using http://preview.community.wikia.com/), exactly the same as last, it seems... Anybody in a country not on this list cannot use preview/show changes on the edit page in the Oasis skin (most notable issues) and other assorted issues too, due to a uncaught JavaScript error.

Edit: corrected country list link