CSS line-height reveals the platform Tor Browser is running on

Dr. Neal Krawetz reported via HackerOne that it is possible to detect the platform a Tor Browser is running with the CSS line-height attribute: 19px is used on Linux, 19.5167px on macOS, and 19.2px or 20px on Windows.

We could think about adjusting that to 20px independent of the platform Tor Browser is running on.