Hello,
The composer.json for VisualEditor is not entirely valid:
./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.
This prevents the publishing of the extension on Packagist and makes it a lot less easy to install with Composer.
Here is an example of a valid composer.json file: https://git.wikimedia.org/blob/mediawiki%2Fextensions%2FLiquidThreads.git/master/composer.json
Regards,