A more permanent solution, however, would be allowing LibreWolf access to UPower's DBus interface:
Description
The UPower service is available via the system message bus. To access the service, use the org.freedesktop.UPower interface on the /org/freedesktop/UPower object on the D-Bus system bus service with the well-known name org.freedesktop.UPower.
Which can be accomplished with the following command:
LibreWolf shows this warning message on the terminal when you open some websites:
In some cases, it is triggered after some obfuscated Cloudflare script is loaded.
AskUbuntu's contact page is an example: After this script loads, the warning shows up in the terminal.
The following uBlock Origin rule silences the warning (at least on AskUbuntu):
A more permanent solution, however, would be allowing LibreWolf access to UPower's DBus interface:
Which can be accomplished with the following command: