screen.orientation should lie
For Firefox 43, Mozilla added a new orientation API that includes the unprefixed screen.orientation property and possibly support for onchange events. See: https://developer.mozilla.org/en-US/docs/Web/API/Screen/orientation https://w3c.github.io/screen-orientation/ Although the patch for #13025 (moved) was upstreamed, the implementation of the new API did not carry forward the concept of respecting the privacy.resistFingerprinting pref.