Cloning one of the mediawiki/skins/* repositories via git into the skins/ directory of your MediaWiki installation.
Doing this should not interfere with your git repository if you're a MediaWiki developer.
If you have just upgraded MediaWiki
MediaWiki 1.24 and newer no longer automatically enables installed skins (see Manual: Skin autodiscovery). You can paste the following lines into LocalSettings.php to enable all currently installed skins:
If you have just modified LocalSettings.php
Double-check the skin names for typos.
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