Librewolf shows “some of LibreWolf’s security features may offer less protection on your current operating system”

I'm test driving Ubuntu after using Gentoo for years and found Librewolf gave me this warning banner.

“some of LibreWolf’s security features may offer less protection on your current operating system”

I searched a bit and found a Mozilla article but it wasn't quite right so I'm documenting here what it is on Ubuntu 24.10

open a terminal window

run

sudo vi /etc/apparmor.d/librewolf

 

and paste in this:

 

# This profile allows everything and only exists to give the
# application a name instead of having the label "unconfined"
abi <abi/4.0>,
include <tunables/global>
profile librewolf
/usr/share/librewolf/librewolf
flags=(unconfined) {
    userns,
    # Site-specific additions and overrides. See local/README for details.
    include if exists <.librewolf>
}

then run

 sudo systemctl restart apparmor.service

The warning banner should not be there next time you open Librewolf.