> Not sure why you'd want to replace the backend, this could break other extensions. Both WebExtensions and Chrome extensions allow changing/deleting browser history items, which should enable most things extensions would want to do.

As I said above, the whole point is to do my own history tracking system, which stores history via a sync system of my own, in a server of my own.

And loads it from there, too.

The user has a webinterface, mobile interface, app integration with browsers, etc.

You can easily do fulltext search of all sites you’ve ever visited, etc.

"Breaking" other extensions is intentional – I want to replace the backend in which they search.

I want to provide far more than what any of these browsers provide, although Vivaldi is still the closest yet.