Rune Skovbo Johansen has been working on a procedurally generated exploration game called The Cluster for a while. While the game isn’t out yet, he’s published a quite a few posts talking about the internal structures and techniques.
For starters, Rune is responsible for that video about layer-based infinite world generation, and he’s also got some source code for his rolling grid implementation. And here’s a tip about better debugging for your generator.
Helpfully, there’s an overview of the technical aspects of the game, with links to even more blogposts.