The Jargon File (version 4.4.7, 29 Dec 2003):

BDFL


    [Python; common] Benevolent Dictator For Life. Guido, considered in his
    role as the project leader of Python. People who are feeling temporarily
    cheesed off by one of his decisions sometimes leave off the B. The mental
    image that goes with this, of a cigar-chomping caudillo in gold braid and
    sunglasses, is extremely funny to anyone who has ever met Guido in person.