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

{
	"apiVersion": 2,
	"name": "core/subhead",
	"category": "text",
	"attributes": {
		"align": {
			"type": "string"
		},
		"content": {
			"type": "string",
			"source": "html",
			"selector": "p"
		}
	},
	"supports": {
		"inserter": false,
		"multiple": false
	}
}