Why doesn't Yahoo have a ticker symbol for The Stock Exchange of Thailand (SET)?

SET is indeed the 'correct symbol', BUT NOT ON YAHOO! Yahoo does not appear to track the Thai SET index. Bloomberg names the same index as SET:IND, but neither that variant, nor the symbol SET, can be found in Yahoo's symbol lookup. If one tries "^SET", one gets the S&P 500 INDEX OPEN FLEX SETTLEM.