Creating a block with ACF

Prototype:register_block_type( string|WP_Block_Type $block_type, array $args = array() ): WP_Block_Type|false

add_action( 'init', 'dev__register_blocks', 5 );

function dev__register_blocks() {
	register_block_type( __DIR__ . '/some_block_dir' );
}

The block.json file :

{
    "$schema": "https://schemas.wp.org/trunk/block.json",
    "apiVersion": 3,
    "name": "namespace/blockname",
    "title": "Notice",
    "category": "text",
    "parent": [ "core/group" ],
    "icon": "star",
    "description": "Shows warning, error or success notices...",
    "keywords": [ "alert", "message" ],
    "version": "1.0.3",
    "textdomain": "my-plugin",
    "editorScript": "file:./index.js",
    "script": "file:./script.js",
    "viewScript": [ "file:./view.js", "example-shared-view-script" ],
    "editorStyle": "file:./index.css",
    "style": [ "file:./style.css", "example-shared-style" ],
    "render": "file:./render.php",
	"supports": {
		"className": true,
		"customClassName": true,
		"jsx": true			// to use innerBlocks,
		"inserter": true	// will be accessible only programatically
	},

	// ACF options: 
	"acf": {
		"mode": "preview",
		"renderTemplate": "render.php"
	},

	"example": { "attributes": { "mode": "preview" } }


}

Sources: