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.
I definitely would use that. I really like the concept.
I often keep a bunch of tabs opened for my multiple ongoing projects. I could close most of them and just query my AI.
As per usual, Mozilla seeking experimental stuff for their browser instead of creating things that would be likely more accessible then the framework required for AI