The clause "by user basis" seems grammatically incorrect and makes little sense. There is a more understandable description on the extension's page (https://www.mediawiki.org/wiki/Extension:AccessControl). I suggest changing this message to: "Allows restricting access to specific pages based on internal groups or group lists from user space."
URL: https://translatewiki.net/wiki/MediaWiki:Accesscontrol-desc/en