Nest is a declarative framework for multi-node NixOS infrastructure. It applies the CSS mental model to system configuration: nodes are entities in a DOM tree, traits are classes, and rules map selectors to configuration.
Nest was used to exercise sini/gen-scope, and related gen-* libraries being built for future Den graphs. As a way that allows us to explore new paths without affecting current API and stability that Den users expect.
See annotated templates/default for a taste of it and docs for concepts guide.