What is NEAT (Neuroevolution of Augmenting Topologies)?

I have looked up what NEAT is on youtube and the internet, but I can only find projects using NEAT, but apart from the wikipedia entry (which only says what it is in introduction, and is very confusing), I still have no idea what it is, is it a library, is it a type of neural network, is it a method of training neural networks? Sorry if this is an obvious question.