Manual:$wgSitename

Details
The name of the site, as displayed throughout the site.

This setting should always be set from LocalSettings.php. The MediaWiki installer usually handles this – the value provided during initial setup is included in LocalSettings.php once the setup process is completed successfully.

This name gets included many times throughout the system. For instance, the Wikipedia tagline "'From Wikipedia, the free encyclopedia."' makes use of this setting. It is mainly used through the magic word " ".

If $wgMetaNamespace (the "project" namespace) is not set, it will be automatically initialized to this value. Make sure the name is appropriately formatted: valid title characters, etc. Also, it cannot be empty, contain the # character, or be the string "MediaWiki".