kazulog@sv1:~$ dpkg -l unattended-upgrades | tail -1
ii  unattended-upgrades 2.12ubuntu9  all          automatic installation of security upgrades
kazulog@sv1:~$ cat /etc/apt/apt.conf.d/20auto-upgrades
APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Unattended-Upgrade "1";
kazulog@sv1:~$ apt-config dump APT::Periodic
APT::Periodic "";
APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Download-Upgradeable-Packages "0";
APT::Periodic::AutocleanInterval "0";
APT::Periodic::Unattended-Upgrade "1";
kazulog@sv1:~$ systemctl status unattended-upgrades --no-pager -l | head -8 | cat
● unattended-upgrades.service - Unattended Upgrades Shutdown
     Loaded: loaded (/usr/lib/systemd/system/unattended-upgrades.service; enabled; preset: enabled)
     Active: active (running) since Thu 2026-09-10 16:18:20 JST; 31s ago
 Invocation: 4c3cdd457ec840ce8982daa12d140003
       Docs: man:unattended-upgrade(8)
   Main PID: 1090 (unattended-upgr)
      Tasks: 2 (limit: 1486)
     Memory: 15M (peak: 15.2M)
kazulog@sv1:~$ systemctl list-timers 'apt-daily*' --no-pager
NEXT                        LEFT LAST                        PASSED UNIT                    ACTIVATES
Fri 2026-09-11 02:45:01 JST  10h Thu 2026-09-10 13:30:25 JST      - apt-daily.timer         apt-daily.service
Fri 2026-09-11 06:05:55 JST  13h Thu 2026-09-10 13:30:25 JST      - apt-daily-upgrade.timer apt-daily-upgrade.service

2 timers listed.
Pass --all to see loaded but inactive timers, too.
kazulog@sv1:~$ systemctl cat apt-daily-upgrade.timer | cat
# /usr/lib/systemd/system/apt-daily-upgrade.timer
[Unit]
Description=Daily apt upgrade and clean activities
After=apt-daily.timer

[Timer]
OnCalendar=*-*-* 6:00
RandomizedDelaySec=60m
Persistent=true

[Install]
WantedBy=timers.target
kazulog@sv1:~$ grep -vE '^\s*//|^$' /etc/apt/apt.conf.d/50unattended-upgrades | head -30
Unattended-Upgrade::Allowed-Origins {
	"${distro_id}:${distro_codename}";
	"${distro_id}:${distro_codename}-security";
	"${distro_id}ESMApps:${distro_codename}-apps-security";
	"${distro_id}ESM:${distro_codename}-infra-security";
};
Unattended-Upgrade::Package-Blacklist {
};
Unattended-Upgrade::DevRelease "auto";