/usr/lib/apt/apt-helper download-file https://debian.sur5r.net/i3/pool/main/s/sur5r-keyring/sur5r-keyring_2023.02.18_all.deb keyring.deb SHA256:a511ac5f10cd811f8a4ca44d665f2fa1add7a9f09bef238cdfad8461f5239cc4
$ sudo apt install ./keyring.deb
$ echo "deb http://debian.sur5r.net/i3/ $(grep '^DISTRIB_CODENAME=' /etc/lsb-release | cut -f2 -d=) universe" | sudo tee /etc/apt/sources.list.d/sur5r-i3.list
$ sudo apt update
$ sudo apt install i3