sudo apt update && sudo apt install -y wget gnupg lsb-release apt-transport-https ca-certificates

wget -O- https://repo.librewolf.net/keyring.gpg | sudo gpg --dearmor -o /usr/share/keyrings/librewolf.gpg

sudo tee /etc/apt/sources.list.d/librewolf.sources <<EOF >/dev/null
Types: deb
URIs: https://repo.librewolf.net
Suites: librewolf
Components: main
Architectures: amd64 arm64
Signed-By: /usr/share/keyrings/librewolf.gpg
EOF

sudo apt update

sudo apt install librewolf -y

sudo dnf config-manager --add-repo https://repo.librewolf.net/librewolf.repo

sudo dnf install librewolf

You should accept any prompts wanting to import the GPG key with the fingerprint 662E3CDD6FE329002D0CA5BB40339DD82B12EF16.