T249047: [Site Config] Make new logos available in production in preparation for T246170 added taglines and icons to the $wgLogos definition, apparently so that $wgMobileFrontendLogo could be removed (T248500). The problem is that these new keys are not documented anywhere!
From the associated commits rOMWC9065650029e45f02438a90e306c0837b82f4019b and rOMWCb8b051fee1b85522b9002dc5b2c618e37b8977f1, I can derive that icon links to an image file, and that tagline defines an <img> specification, with a src, width and height attribute. What they're actually for is not mentioned.
Definition of Done
- DefaultSettings.php mentions the new keys
- The release notes section on $wgLogos mentions the new keys
- Documentation on MediaWiki specifies a description of the keys, the kind of image they expect and when they should be used
- Installer takes into account the new keys