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

{
	"apiVersion": 2,
	"name": "core/block",
	"category": "reusable",
	"attributes": {
		"ref": {
			"type": "number"
		}
	},
	"supports": {
		"customClassName": false,
		"html": false,
		"inserter": false
	}
}