Manual:ValidateRegistrationFile.php

Details
New extension registration mechanism introduced in MediaWiki 1.25 which uses to load extensions and skins through extension.json or skin.json

validateRegistrationFile.php maintenance script provide a way to validate that extension.json or skin.json. See Manual:Extension_registration.

Arguments
validateRegistrationFile.php accepts only path or glob pattern of extension.json/skin.json as an argument.