Source

File: wp-includes/media.php

function get_taxonomies_for_attachments( $output = 'names' ) {
	$taxonomies = array();

	foreach ( get_taxonomies( array(), 'objects' ) as $taxonomy ) {
		foreach ( $taxonomy->object_type as $object_type ) {
			if ( 'attachment' === $object_type || 0 === strpos( $object_type, 'attachment:' ) ) {
				if ( 'names' === $output ) {
					$taxonomies[] = $taxonomy->name;
				} else {
					$taxonomies[ $taxonomy->name ] = $taxonomy;
				}
				break;
			}
		}
	}

	return $taxonomies;
}