The Blackout extension doesn't currently have its own phab project. I'm going to put it in the review queue and thus I'd like to ask for a new project to be created. I guess the name should be Mediawiki-extension-Blackout, standard policy, and a description like
Project for the Blackout extensions, which allows to prevent site access. See the [[https://www.mediawiki.org/wiki/Extension:Blackout|homepage]] on mediawiki.org.