bbPress.org

You also go about it this way by adding it to your themes functions.php file or your bbpress-functions.php file in your theme directory.

To change from Home › Forums › My ForumSubscribe
To change to Home › Forums › My Forum (Subscribe)

function ntwb_forum_subscription_link( $args ) {
    $args['before'] = ' (';
    $args['after']  = ')';
 
    return $args;
}
 
add_filter( 'bbp_before_get_forum_subscribe_link_parse_args', 'ntwb_forum_subscription_link' );

If you don’t want to add it manually grab the entire file here and add it as a standalone plugin to your WordPress install.

https://gist.github.com/ntwb/7686980