The generator was created using a modified version of the Wave Function Collapse algorithm.
Developer Samuel Lundsten continues experimenting with Wave Function Collapse (WFC), a neat algorithm that can generate procedural patterns from a sample image, and showcasing impressive projects achieved with it.
This time, the creator demonstrated an incredible generator capable of creating procedural forest maps with navigable tiles. According to the author, the generator is powered by a modified version of WFC, which has been rewritten to have "a good navigability heuristic and some other neat stuff."
And here are some of the author's earlier projects: