This Extension provides a Google Login Special page to login with a Google account to a the MediaWiki User account.
See https://www.mediawiki.org/wiki/Extension:GoogleLogin
This Extension uses the Google API PHP Client, a free software licensed under Apacha 2.0: https://github.com/google/google-api-php-client https://github.com/google/google-api-php-client/blob/master/LICENSE