_get_block_templates_files() WordPress Function

function _get_block_templates_files( $template_type ) {
	if ( 'wp_template' !== $template_type && 'wp_template_part' !== $template_type ) {
		return null;
	}

	$themes         = array(
		get_stylesheet() => get_stylesheet_directory(),
		get_template()   => get_template_directory(),
	);
	$template_files = array();
	foreach ( $themes as $theme_slug => $theme_dir ) {
		$template_base_paths  = get_block_theme_folders( $theme_slug );
		$theme_template_files = _get_block_templates_paths( $theme_dir . '/' . $template_base_paths[ $template_type ] );
		foreach ( $theme_template_files as $template_file ) {
			$template_base_path = $template_base_paths[ $template_type ];
			$template_slug      = substr(
				$template_file,
				// Starting position of slug.
				strpos( $template_file, $template_base_path . DIRECTORY_SEPARATOR ) + 1 + strlen( $template_base_path ),
				// Subtract ending '.html'.
				-5
			);
			$new_template_item = array(
				'slug'  => $template_slug,
				'path'  => $template_file,
				'theme' => $theme_slug,
				'type'  => $template_type,
			);

			if ( 'wp_template_part' === $template_type ) {
				$template_files[] = _add_block_template_part_area_info( $new_template_item );
			}

			if ( 'wp_template' === $template_type ) {
				$template_files[] = _add_block_template_info( $new_template_item );
			}
		}
	}

	return $template_files;
}