Amirouche suggested using ordinary markdown files in a Git repo instead of GitHub's wiki since it's easier to manage things with pull requests and edit locally. That may be better for the long run.

I support that opinion, I would also prefer Markdown (or Org-mode) to GH Wiki.

I think it would be good if each kind of scraper was eventually its own self-contained library (that can also be turned into a self-contained executable program with the help of a little 'main' procedure that calls the library).  [...]

Sounds good, so fine for me. Just feel free to dismantle the current SRFI-collector as you like ;)