post_type_archive_title( string $prefix = '', bool $display = true )

function post_type_archive_title( $prefix = '', $display = true ) {
	if ( ! is_post_type_archive() )
		return;

	$post_type = get_query_var( 'post_type' );
	if ( is_array( $post_type ) )
		$post_type = reset( $post_type );

	$post_type_obj = get_post_type_object( $post_type );

	/**
	 * Filters the post type archive title.
	 *
	 * @since WP-3.1.0
	 *
	 * @param string $post_type_name Post type 'name' label.
	 * @param string $post_type      Post type.
	 */
	$title = apply_filters( 'post_type_archive_title', $post_type_obj->labels->name, $post_type );

	if ( $display )
		echo $prefix . $title;
	else
		return $prefix . $title;
}