sources.list.amd64

deb https://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
deb https://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse