@Bawolff: Thanks for adding the new 'Quarterly downloads' figures! Looks great. I think we should link it to a page that explains what the numbers mean and where they come from. It's counting ExtensionDistributor downloads isn't it?
Topic on Template talk:Extension
Yes, that sounds like a good idea. The data is from graphite which is the same source of data powering the popular list on special:SkinDistributor.
After looking through some of the less popular extensions, i'm wondering if quarterly is a big enough sample size. Perhaps yearly downloads would make more sense.
I've created a section at Manual:Extensions#Popular_extensions. Manual:Installing extensions redirects to that page, so it seemed appropriate.
And yeah, maybe annual would be better. Also, we could probably retrieve Packagist stats too and add those for Composer-installable extensions.
Oh i didn't even think of packagist, although I'm not sure if there are enough composer extensions to make it worth it.
I'm also a bit doubtful of some of their stats. I just find it hard to believe that Semantic MediaWiki has been installed 240,000 times - https://packagist.org/packages/mediawiki/semantic-media-wiki/stats
Oh yeah, maybe there's some CI downloads included? That does sound like a large number. There are lots like that! https://packagist.org/?type=mediawiki-extension Although I guess it does include every download of every upgrade too.
There are 326 in Category:Extensions supporting Composer. I don't think all of them actually are registered with Packagist though. (But weirdly, the search results response on Packagist (e.g.) has a 'nbHits' field which is exactly 326! Definitely a different list though as e.g. bluespice/rating isn't on Packagist but has a Composer name.)