> It would take about 15 minutes to create a browser extension that could make a hash of all the files loaded, to compare with other users with the extension installed

You completely underestimate it. I am absolutely certain that you cannot create a browser extension that meaningfully solves this problem in 15 minutes.

> Web applications are sandboxed in the web browser. Very little issue with that

Except that when we are talking about end-to-end encryption, the sandbox has nothing to do with it. The sandbox defends against something else, not the server serving you an end-to-end encryption program abusing it.

> AWS has a web-based terminal for EC2 instances. It's not a problem, a lot of people use it.

I genuinely can't see if you just don't understand the point being discussed at all, or if you keep saying off-topic things as a way to divert the discussion.