http://ttevhjjsjxz6uqqcjkbig5cycd7n7xv7cmd6f5fcvrqaaa7f3bj36wad.onion/technology/security/pow/index.html
When the client first attempts to solve a client puzzle, it can estimate of the
duration of the PoW. In the future, this estimation could be displayed in the
application, such that the browser could display how long the PoW is expected
to take on their device. If the device is a mobile platform, and this time estimation is large, it could
recommend that the user try from a desktop machine.