Below is an example of a sources.list for Debian 12/Bookworm (stable).
These are the normal sources your system should have.
If you need the contrib, non-free and non-free-firmware components, add contrib non-free non-free-firmware after main. For example, for Debian 12/Bookworm.
Note: If you do not need contrib, do not add it. This will bring packages and dependencies from outside of Debian into your system and may introduce instability.
These are the normal sources your system should have.
Code:
deb http://deb.debian.org/debian bookworm main non-free-firmware
deb-src http://deb.debian.org/debian bookworm main non-free-firmware
deb http://deb.debian.org/debian-security/ bookworm-security main non-free-firmware
deb-src http://deb.debian.org/debian-security/ bookworm-security main non-free-firmware
deb http://deb.debian.org/debian bookworm-updates main non-free-firmware
deb-src http://deb.debian.org/debian bookworm-updates main non-free-firmwareIf you need the contrib, non-free and non-free-firmware components, add contrib non-free non-free-firmware after main. For example, for Debian 12/Bookworm.
Note: If you do not need contrib, do not add it. This will bring packages and dependencies from outside of Debian into your system and may introduce instability.
Code:
deb http://deb.debian.org/debian bookworm main contrib non-free non-free-firmware
deb-src http://deb.debian.org/debian bookworm main contrib non-free non-free-firmware
deb http://deb.debian.org/debian-security/ bookworm-security main contrib non-free non-free-firmware
deb-src http://deb.debian.org/debian-security/ bookworm-security main contrib non-free non-free-firmware
deb http://deb.debian.org/debian bookworm-updates main contrib non-free non-free-firmware
deb-src http://deb.debian.org/debian bookworm-updates main contrib non-free non-free-firmware