myself and the other founding engineer are no longer with the company, but it's still out there in some form. last I heard they are still planning on shipping an interesting web browser extension, though not using the novel tech stack I had been working on:

GitHub

GitHub - operating-function/packrat: Next-gen browser history

Next-gen browser history. Contribute to operating-function/packrat development by creating an account on GitHub.

I'm looking forward to seeing how it goes.