In the file /qa-include/qa-db-users.php, there is for instance the following function call:
qa_db_query_sub('INSERT INTO ^users (created, createip, email, passsalt, passcheck, level, handle, loggedin, loginip) '. 'VALUES (NOW(), COALESCE(INET_ATON($), 0), $, $, UNHEX($), #, $, NOW(), COALESCE(INET_ATON($), 0))',$ip, $email, $salt, isset($password) ? qa_db_calc_passcheck($password, $salt) : null, (int)$level, $handle, $ip);
I do understand that the $ signs get replaced with the values which are specified furter. But what is the # sign doing there?