Meta Box

The current is the one that is defined in the rwmb_meta_boxes filter: 'post_types' => 'testtype'

I need to load the $content variable only on the testtype and not on the default post type.

The code is something like this:

add_filter( 'rwmb_meta_boxes', 'test' );
function test( $meta_boxes ) {
	
	// Get current post ID
	$post_id = false;
	if ( isset( $_GET['post'] ) ) {
		$post_id = intval( $_GET['post'] );
	}
	elseif ( isset( $_POST['post_ID'] ) ) {
		$post_id = intval( $_POST['post_ID'] );
	}
	
    if ( get_post_status( $post_id ) != 'publish' ) {
    	$content = 'Not Published';
    } else {
    	$content = 'Published';
    }
    
    $meta_boxes[] = array(
        'title'      => esc_html__( 'Test', 'test' ),
		'post_types' => 'testtype',
		'context'    => 'side',
		'priority'   => 'low',
        'fields'     => array(
			array(
				'id'   => "_test",
				'type' => 'custom_html',
				'std'  => $content,
			),
		)
	);
	
	return $meta_boxes;
}