I think AV vendors used to do browser addons to provide some functionality. But since browser extensions in all popular browser are now effectively neutered ver

I think AV vendors used to do browser addons to provide some functionality. But since browser extensions in all popular browser are now effectively neutered versions of their former selves, they are probably resorting to stuff like this. It can be hard to even get a browser addon installed as a third party program without resorting to hacks (thanks to browsers having taken measures after the toolbar hell).