WordPress at a glance
function is not described

use_block_editor_for_post_type() WP 5.0.0

Return whether a post type is compatible with the block editor.

The block editor depends on the REST API, and if the post type is not shown in the REST API, then it won't work with the block editor.

Hooks in function
Return

true/false. Whether the post type can be edited with the block editor.

Usage

use_block_editor_for_post_type( $post_type );
$post_type(string) (required)
The post type.

Code of use block editor for post type: wp-admin/includes/post.php VER 5.1.1

<?php
function use_block_editor_for_post_type( $post_type ) {
	if ( ! post_type_exists( $post_type ) ) {
		return false;
	}

	if ( ! post_type_supports( $post_type, 'editor' ) ) {
		return false;
	}

	$post_type_object = get_post_type_object( $post_type );
	if ( $post_type_object && ! $post_type_object->show_in_rest ) {
		return false;
	}

	/**
	 * Filter whether a post is able to be edited in the block editor.
	 *
	 * @since 5.0.0
	 *
	 * @param bool   $use_block_editor  Whether the post type can be edited or not. Default true.
	 * @param string $post_type         The post type being checked.
	 */
	return apply_filters( 'use_block_editor_for_post_type', true, $post_type );
}