To submit a community plugin this is the json content to create pull request with:

{
	"npm": "the npm package name of your plugin",
	"author": "Your Twitter username",
	"description": "A description of the plugin"
}

Does it need to be a Twitter/X handle? What effect does it have besides

Already a supporter but it’s not showing here? Make sure your Twitter account is listed on your Open Collective Profile.
— example of a profile on 11ty.dev/authors/

I’m not active on Twitter/X anymore and I asume lots of 11ty folks are neither.