At this point, it does a GIANT pile of additional things most of which are specific to my interests, but I think it might be at least marginally interesting to others.

It does both full autonomous web-spidering of sites you specify, as well as synchronous rendering (You can browse other sites through it, with it rewriting all links to be internal links, and content for unknown sites fetched on-the-fly).

I solve the javascript problem largely by removing all of it from the content I forward to the viewing client, though I do support remote sites that load their content through JS via headless chromium (I wrote a library for managing chrome that exposes the entire debugging protocol here: https://github.com/fake-name/ChromeController https://pypi.org/project/ChromeController/).