For a skin running on the mobile domain, MediaWiki:Mobile.(css|js) should be run. (the mobile.site and mobile.site.styles modules)
For a skin running on the desktop domain, MediaWiki:Common.(css|js) should be run (the site and site.styles modules)
=== Acceptance criteria
 The `site` and `site.styles` modules no longer use a ResoureLoader targets filter.
 MobileFrontend still ensures the desktop-specific pages of these modules don't load on mobile, and that the mobile versions of these load instead.
== Developer notes
Rather than relying on the targets system, MobileFrontend could remove the `site` module explicitly via a hook
This hook would need to run at the start of OutputPage::loadSkinModules or at the end of Skin:::getDefaultModules. Given Minerva runs a hook in the latter, it seems we have precedent for that hook to run there.
Hooks::run( 'SkinMinervaDefaultModules', [ $this, &$modules ] );
MobileFrontend can subscribe to the new hook and eventually SkinMinervaDefaultModules can be removed.
== Sign off
 Test and sign off T140045 which should be fixed by this change.