传统格式：

sudo nano /etc/apt/sources.list

# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm main contrib non-free non-free-firmware
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm main contrib non-free non-free-firmware

deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-updates main contrib non-free non-free-firmware
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-updates main contrib non-free non-free-firmware

deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-backports main contrib non-free non-free-firmware
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-backports main contrib non-free non-free-firmware

# 以下安全更新软件源包含了官方源与镜像站配置，如有需要可自行修改注释切换
deb https://security.debian.org/debian-security bookworm-security main contrib non-free non-free-firmware
# deb-src https://security.debian.org/debian-security bookworm-security main contrib non-free non-free-firmware

DEB822 格式

/etc/apt/sources.list.d/debian.sources

Types: deb
URIs: https://mirrors.tuna.tsinghua.edu.cn/debian
Suites: bookworm bookworm-updates bookworm-backports
Components: main contrib non-free non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg

# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
# Types: deb-src
# URIs: https://mirrors.tuna.tsinghua.edu.cn/debian
# Suites: bookworm bookworm-updates bookworm-backports
# Components: main contrib non-free non-free-firmware
# Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg

# 以下安全更新软件源包含了官方源与镜像站配置，如有需要可自行修改注释切换
Types: deb
URIs: https://security.debian.org/debian-security
Suites: bookworm-security
Components: main contrib non-free non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg

# Types: deb-src
# URIs: https://security.debian.org/debian-security
# Suites: bookworm-security
# Components: main contrib non-free non-free-firmware
# Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg