Composer for extension management was declined (see T467).
But it can and should be used, if our extension provides library functionality, which others can depend on. And that's the case for the UserNameSessionProvider class, which isn't Auth_remoteuser-specific. Other (auth) extensions can use/inherit from this class to not maintain a SessionProvider class on their own.
Additionally the extension code itself can be installed with composer (but not enabled! that must be done with MW extension registration).
Therefore providing composer support for this extension could be useful.
- Merge Patch Set with valid composer.json
- Push at least one valid version tag to repository
- Submit extensions repository link to mediawiki user on packagist.org