If you are not an extension developer, you can safely ignore this message. I am excited to announce that the Minerva Neue skin will be bundled with MediaWiki in 1.38 per https://phabricator.wikimedia.org/T191743 The Minerva Neue skin powers the mobile site of Wikimedia projects, so it makes sense to include this skin for 3rd party MediaWiki instances that want a responsive but simplified experience. The implication of this is that extension developers should be making sure their code compatible with MinervaNeue. Note, that Minerva Neue operates in two modes (a desktop or mobile mode) depending on whether MobileFrontend is installed, however, MobileFrontend is still not part of the MediaWiki bundle so this mode doesn't need to be tested at this point. You can tell if you are in Minerva desktop mode by testing in an incognito window and verifying that you see a more (ellipsis) dropdown in the toolbar. e.g. Test on https://en.wikipedia.org/wiki/Minerva?useskin=minerva NOT https://en.m.wikipedia.org/wiki/Minerva?useskin=minerva if you have any questions or concerns please feel free to reply to this e-mail or the Phabricator ticket. Thanks for reading! Jon