A few quick thoughts: * One could argue the mediawiki.ui implementation was never destined to become a standard/default implementation to begin with. The design is staying (or that direction at least), but not the implementation. However that didn't prevent people from using those classes outside the intended usage area (e.g. selected areas in core and certain extensions that need the look and feel now, while OOjs UI was being worked on). I warned against this when it was added to the default page modules, but alas. I guess people either didn't realise what it meant or are okay with having to migrate twice (once to mw.ui.less and now to oojs-ui). * The factor of how easy a class is for a human to grok is mostly irrelevant. OOjs UI's API isn't single classes. The HTML isn't meant to be written by hand on a page.[2] To achieve the features we need and, more importantly, browser support; a single element with some classes doesn't suffice. The browser's themselves have a lot more than one element, too. They just hide it via ShadowDOM.[1] Until we can either reliably use CSS3 and CSS4 features or HTML5 Web Components across browsers, we'll need most widgets to be two or three elements in the public DOM. Another reason for not maintaining such HTML by hand is because it can change and you'll want to keep maintenance central and minimal for when that happens. We'll keep breaking changes to a minimum (especially those requiring html changes), but expect them to happen (especially in the first year). * Perhaps we should freeze mediawiki-ui. Then keep around until we're comfortable removing it. No new features, design syncs or other changes. Focus efforts on OOjs UI, and slowly migrate towards that. Including OOjs UI "no-js" entry point where a lighter html footprint is required. — Timo [1] Here's an example of Chrome rendering a simple input field with placeholder and a number input field, exposing the internal elements the browser utilises to render it: http://i.imgur.com/CWQ2Htj.png [2] This is easy for JS and PHP, but for wiki pages the community should use an abstraction for that html. Templates or Lua modules are the appropriate venue for that. On 8 Jan 2015, at 04:18, S Page &lt;spage(a)wikimedia.org&gt; wrote: (I couldn't find a list for "Frontend standards group" and I'm not sure if all its engineers are on the design list.) I congratulated James_F on IRC for VisualEditor/ OOjs UI adopting the mediawiki.ui style, but then it went topsy-turvy: *spagewmf* I missed that VisualEditor is now using the mediawiki.ui style formerly known as "Agora" *James_F* No, we are not. Agora and MediaWiki.ui are both previous designs. This one is different, apparently. Don't ask me how. :-) It's mostly similar, at least. It's the MediaWiki Theme for OOjs UI. *spagewmf* How is WMF keeping the "simple" mw-ui-button mw-ui-constructive and OOjs UI's more elaborate oo-ui-widget > oo-ui-buttonElement oo-ui-flaggedElement-constructive CSS in sync? Are we able to share LESS rules? *James_F* MW UI isn't being kept in sync with the new design, I believe. I don't think it's credible to try to marry the technologies together with shared files – it'd be a huge amount of work for a short-term hack. *spagewmf* The mw-ui- classes are a lot easier for humans to grok/reuse, e.g. https://en.wikipedia.org/wiki/Template:Clickable_button It could be very cool for pages to have OOjs UI gadgets someday. *James_F* Well, tough. :-) MW-UI won't be around for much longer. How soon is "short-term" and "not much longer"? It's less than a year since mediawiki.ui.button made it into the default set of page modules and the Living Style Guide <http://tools.wmflabs.org/styleguide/desktop/section-2.html> appeared. Are devs going to continue working on $wgUseMediaWikiUIEverywhere to deliver UX consistency? I understand the approach espoused by the Frontend standards group <https://www.mediawiki.org/wiki/Frontend_standards_group> is "use OOjs UI <https://www.mediawiki.org/wiki/OOjs_UI> components" and I'm excited to see Bartosz prototyping the UserLogin form in oojs-ui/php. But it'll be a long time before the 15 extensions using mediawiki.ui have all transitioned to OOjs UI. I look forward to the "Frontend standards" session at the developer summit. “The future has arrived — it’s just not evenly distributed yet.” Cheers, -- =S Page WMF Tech writer