The informal, slightly tongue-in-cheek title given to a respected individual in the open source development community who sets general directions and makes final calls in certain situations within the scope of a given project. The BDFL is a tacit acknowledgement that communal, consensus-based decision making within the open source community occasionally runs up against obstacles, in which case a single authoritative voice can be useful. That BDFLs survive and flourish in these otherwise anarchistic contexts is attributed to their personal charisma and their reluctance to wield their power except in rare moments.
Of course, a project coordinator cannot really be anything like a dictator in the sense that he or she ultimately cannot enforce a decision, since a project fork is always possible.
Not all, or even most, open source projects have a BDFL.
Note the difference from the historical meaning of benevolent dictator, which is used in a political context.
List of Benevolent Dictators for Life
Drupal content management framework
Linus Torvalds, explicitly recognising the "benevolent dictator" epithet, e.g. in the interview published August 18, 2004 in Business Week
OpenBSD operating system
Theo de Raadt
Perl programming language
PHP programming language
Python programming language
Guido van Rossum, known for his co...