> the user must be able to clear it when clearing site data and this what makes it currently an unviable solution What are you suggesting here? That extensions

> the user must be able to clear it when clearing site data and this what makes it currently an unviable solution What are you suggesting here? That extensions should have some special storage, that can't be (easily) deleted? Noooooooo thank you. Firefox has "forget about this site" and similar tools, which I use near daily. Don't fuck with my ability to do housekeeping.