The following setting should be part of the default privacy settings:
lockPref("dom.event.clipboardevents.enabled", false);
You can take a look at:
https://support.mozilla.org/si/questions/969543
Particularly the comment from jscher2000 there.
Welcome to the official community for LibreWolf.
LibreWolf is designed to increase protection against tracking and fingerprinting techniques, while also including a few security improvements. LibreWolf also aims to remove all the telemetry, data collection and annoyances, as well as disabling anti-freedom features like DRM. If you have any question please visit our FAQ first: https://librewolf.net/docs/faq/
To learn more or to download the browser visit the website: https://librewolf.net/
If you want to contribute head over to our Gitlab: https://gitlab.com/librewolf-community/browser
not worth it at best -> https://github.com/arkenfox/user.js/issues/1081#issuecomment-906560952
Thanks !