bp_groups_get_group_type( int $group_id, bool $single = true )

function bp_groups_get_group_type( $group_id, $single = true ) {
	$types = wp_cache_get( $group_id, 'bp_groups_group_type' );

	if ( false === $types ) {
		$raw_types = bp_get_object_terms( $group_id, 'bp_group_type' );

		if ( ! is_wp_error( $raw_types ) ) {
			$types = array();

			// Only include currently registered group types.
			foreach ( $raw_types as $gtype ) {
				if ( bp_groups_get_group_type_object( $gtype->name ) ) {
					$types[] = $gtype->name;
				}
			}

			wp_cache_set( $group_id, $types, 'bp_groups_group_type' );
		}
	}

	$type = false;
	if ( ! empty( $types ) ) {
		if ( $single ) {
			$type = end( $types );
		} else {
			$type = $types;
		}
	}

	/**
	 * Filters a groups's group type(s).
	 *
	 * @since BuddyPress 2.6.0
	 *
	 * @param string|array $type     Group type.
	 * @param int          $group_id ID of the group.
	 * @param bool         $single   Whether to return a single type string, or an array.
	 */
	return apply_filters( 'bp_groups_get_group_type', $type, $group_id, $single );
}