https://github.com/Mozilla-Ocho/Memory-Cache is the actual project if you want to use it.
Basically it's a firefox extension to save a page as a pdf in a directory that is symlinked to your local PrivateGPT install which then ingests the docs. It doesn't seem to me that it provides any in-browser querying of PrivateGPT but I haven't tried setting it up to confirm that.