ResourceLoaderULSModule updates its modified time whenever ResourceLoaderContext::getLanguage varies. ResourceLoaderContext::getLanguage varies gets the language via the 'lang' parameter on the module request. The lang parameter is set in mediawiki.js to wgUserLanguage.

Result: the version of ext.uls.languagenames is updated continuously as users with different language settings hit the site, with the effect that practically every request for the module (and any other module fetched in the same request) is uncached.

To confirm this bug report, you can go to enwiki and check mw.loader.getVersion('ext.uls.languagenames'); . Then reload and check again.

'mediawiki.language.data' appears to likewise update continuously.

Version: unspecified
Severity: major