The Benevolent Dictator For Life is a term for an Open Source project leadership model that is commonly used, where the individual who created the project remains the leader and ultimately has the final say and veto on decisions. Oftentimes this power is only implied, not actually written down or pronounced anywhere.
Like with any dictatorship, it is an effective and speedy model that can avoid long and tiresome debates or voting procedures because there is a single person's guidance to keep the course straight. If the dictator takes the wrong turn however, or makes their decrees against what the community thinks is the right way, the model breaks down fairly quickly.
I have worked in several projects with benevolent dictators and I am myself a BDFL some places. In my view, that is not an ideal way to run a project by any means, even if you are the BDFL. It is hard to know where to go and what decisions to make. As a BDFL, I have always made a serious effort to listen to what people say, what they want, and where the world seems to suggest is a suitable place for the project to set its next tent pole.