Modern is a MediaWiki skin.
It was created in 2008.
It was derived from the MonoBook skin.
In MediaWiki 1.23 and earlier, the Modern skin was maintained within the MediaWiki core repository.
In MediaWiki 1.24, along with other default skins, it was separated from core to its own repository.
It remained bundled with MediaWiki until it was removed from the bundle in version 1.31.
It has been available as a user option on Wikimedia wikis since its first version.
It was also the default skin for the Toolserver wiki until Toolserver was shut down in 2014.
This skin is being used on one or more Wikimedia projects. This probably means that the skin is stable and works well enough to be used by such high-traffic websites. Look for this skin's name in Wikimedia's CommonSettings.php and InitialiseSettings.php configuration files to see where it's installed. A full list of the skins installed on a particular wiki can be seen on the wiki's Special:Version page.
This skin is included in the following wiki farms/hosts and/or packages: