添加Debain中文社区软件源

echo "deb https://repo.debiancn.org/ testing main" | sudo tee /etc/apt/sources.list.d/debiancn.list;
wget https://repo.debiancn.org/pool/main/d/debiancn-keyring/debiancn-keyring_0~20161212_all.deb -O /tmp/debiancn-keyring.deb;
sudo apt install /tmp/debiancn-keyring.deb;
sudo apt update;
rm /tmp/debiancn-keyring.deb;

软件源地址 && 软件包一览:https://repo.debiancn.org

删除软件源(如需)

sudo apt purge debiancn-keyring;
sudo rm -f /etc/apt/sources.list.d/debiancn.list;
sudo apt update;

可能用到的镜像地址:
https://mirrors.ustc.edu.cn/debiancn/