it's a list by code (by 639-1) which List of ISO 639-2 codes is not.
 calling it List of ISO 639 codes is not correct once the 639-3 codes are official.
 639-1 is only a small subset. makes the list more handy then 639-2 list
 list could be an easy transition list for people that want to switch from 639-1  or RFC ... to ISO 639-3.
 (Talk)