The goal of this RfC is to solicit requirements and feature requests for what people want MediaWiki's extension management system to do. Unless otherwise stated, the term extension applies to skins as well for simplicity.
Related: https://www.mediawiki.org/wiki/Requests_for_comment/Improving_extension_management (2015)
See also T467: RfC: Extension management with Composer
See also T534: Create a List of Requirements for Extension Management