We are talking about an always available, zero-cost, virtual machine with guaranteed data privacy .
CheerpX is able to run compiled x86 code (so any source language) in the browser with an HTTP based read-only filesystem delivering the OS (Debian in this case), and local writeable storage in the browser (I think). Uses WebAssembly in the browser.
Some ideas for a Safe hosted OS perhaps?
More:
UPDATE:
Try CheerpX Debian Linux in your browser now. Uses a JIT compiler to Web Assembly…
If CheerpX can run Debian and can support a hypervisor like KVM and virtualization manager like libvirt, then you could have a whole other network running in the browser. I don’t know why but you could.