WordPress/wp-includes/blocks/block/block.json

{
	"$schema": "https://schemas.wp.org/trunk/block.json",
	"apiVersion": 2,
	"name": "core/block",
	"title": "Reusable block",
	"category": "reusable",
	"description": "Create and save content to reuse across your site. Update the block, and the changes apply everywhere it’s used.",
	"textdomain": "default",
	"attributes": {
		"ref": {
			"type": "number"
		}
	},
	"supports": {
		"customClassName": false,
		"html": false,
		"inserter": false
	}
}