Headset controls (A.K.A Control media via keyboard, headset, or virtual interface) do not work

The "Control media via keyboard, headset, or virtual interface" part of the browser does not work. For things like youtube and youtube music, it does nothing. I've tried about:config tweaks but couldn't seem to get anything working.

I have this issue too. Couldn't get it to accept anything from AutoHotKey either. This is a real deal-breaker.

Discussion: https://github.com/mullvad/mullvad-browser/issues/236

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