$ composer validate ./composer.json is valid for simple usage with composer but has strict errors that make it unable to be published as a package: See https://getcomposer.org/doc/04-schema.md for details on the schema name : The property name is required description : The property description is required No license specified, it is recommended to do so. For closed-source software you may use "proprietary" as license.
I think we should fix these issues so you can at least specify the extension manually.
It should specify a name as mediawiki/event-logging and a type as mediawiki-extension,