Ubuntu apt

$ find /etc/apt
/etc/apt
/etc/apt/sources.list.d
/etc/apt/sources.list.d/gitlab_gitlab-ce.list.save
/etc/apt/sources.list.d/gitlab_gitlab-ce.list
/etc/apt/sources.list.save
/etc/apt/trusted.gpg.d
/etc/apt/trusted.gpg.d/ubuntu-keyring-2012-cdimage.gpg
/etc/apt/trusted.gpg.d/ubuntu-keyring-2012-archive.gpg
/etc/apt/trusted.gpg.d/ubuntu-keyring-2018-archive.gpg
/etc/apt/trusted.gpg
/etc/apt/auth.conf.d
/etc/apt/apt.conf.d
/etc/apt/apt.conf.d/20snapd.conf
/etc/apt/apt.conf.d/01autoremove-kernels
/etc/apt/apt.conf.d/20packagekit
/etc/apt/apt.conf.d/10periodic
/etc/apt/apt.conf.d/01-vendor-ubuntu
/etc/apt/apt.conf.d/15update-stamp
/etc/apt/apt.conf.d/20archive
/etc/apt/apt.conf.d/20apt-esm-hook.conf
/etc/apt/apt.conf.d/99update-notifier
/etc/apt/apt.conf.d/70debconf
/etc/apt/apt.conf.d/01autoremove
/etc/apt/apt.conf.d/20auto-upgrades
/etc/apt/apt.conf.d/50command-not-found
/etc/apt/apt.conf.d/50unattended-upgrades
/etc/apt/trusted.gpg~
/etc/apt/preferences.d
/etc/apt/sources.list
/etc/apt/sources.list.curtin.old

$ cat /etc/apt/sources.list
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://jp.archive.ubuntu.com/ubuntu focal main restricted
# deb-src http://jp.archive.ubuntu.com/ubuntu focal main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://jp.archive.ubuntu.com/ubuntu focal-updates main restricted
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://jp.archive.ubuntu.com/ubuntu focal universe
# deb-src http://jp.archive.ubuntu.com/ubuntu focal universe
deb http://jp.archive.ubuntu.com/ubuntu focal-updates universe
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://jp.archive.ubuntu.com/ubuntu focal multiverse
# deb-src http://jp.archive.ubuntu.com/ubuntu focal multiverse
deb http://jp.archive.ubuntu.com/ubuntu focal-updates multiverse
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://jp.archive.ubuntu.com/ubuntu focal-backports main restricted universe multiverse
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu focal partner
# deb-src http://archive.canonical.com/ubuntu focal partner

deb http://jp.archive.ubuntu.com/ubuntu focal-security main restricted
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-security main restricted
deb http://jp.archive.ubuntu.com/ubuntu focal-security universe
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-security universe
deb http://jp.archive.ubuntu.com/ubuntu focal-security multiverse
# deb-src http://jp.archive.ubuntu.com/ubuntu focal-security multiverse
deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu focal stable