The name for that is letterboxing. The Tor Browser (and the Mullvad browser, based on the Tor one, and Firefox as of v. 67 with an about:config flag) all suppo

The name for that is letterboxing. The Tor Browser (and the Mullvad browser, based on the Tor one, and Firefox as of v. 67 with an about:config flag) all support it. There are also add-ons that perform the same basic function with some added customisability [0]. [0] https://addons.mozilla.org/en-US/firefox/addon/canvasblocker/ https://addons.mozilla.org/en-US/firefox/addon/canvasblocker...