§1. This is the home page for documentation, human-readable source code and examples for the literate programming system Inweb. It's hosted on the Github Docs area of the Inweb repository, at: https://github.com/ganelson/inweb Download and build instructions are there, not here.
To get a sense of Inweb and what it does, see Manual (in inweb). The simple example twinprimes and goldbach may also help.
But if you're here to look under the hood, or you want to fix a bug or add a feature, a good place to begin is How This Program Works (in inweb).
§2. Inweb is built on top of a library of C functions called foundation, supplied in the same repository. See A Brief Guide to Foundation (in foundation). There's also a small tool for unit-testing it, foundation-test, but this is not an interesting read.