Comment by Hayarotle

They're testing out the new UI in the other language Wikipedias. It adds a nice collapsible topic structure to the sidebar and sets a text width limit, but hides the available languages for the article behind a button on the header. This makes it harder to tell whether the article is available in specific languages, and to switch the language. It's a bit unwieldy as of now, as you now have to jump to the top of the page and click the "languages" button just to check if the article is available in your desired language, but they are showing some effort. They plan to make the header sticky and add direct links to the user's most frequently used languages. I just hope a sticky header doesn't take away much of the space dedicated to the page's content.

Here's a link to the ideas page discussing the change:

https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(propos...

And a link to a page describing the changes:

https://www.mediawiki.org/wiki/Reading/Web/Desktop_Improveme...