Per osTicket #3714, we should add the Liberty skin as an option the users can choose.
I've contributed a few patches to it over the years to make this happen one day...

To-do list:

• Add skin to repo
• Add support for the skin into ShoutWikiAds (leaderboard ad is always available, but we'll probably want some more slots than just that one)
• Actually there's $wgLibertyAdSetting (sic), which is like $wgAdConfig but just for this one skin. We should set that up properly in GlobalSettings.php
• Add screenshots to /extensions/CreateWiki/images (and add the skin to $wgCreateWikiAllowedThemes though that var isn't really used, as per the code comment)
• Configure as desired (may want to turn off the live RC widget by default, $wgLibertyEnableLiveRC = false;, and maybe also Gravatar integration: $wgLibertyUseGravatar = false; -- Twitter stuff etc. needs further looking into)