[email protected]:~$ ls -lat /var/lib/apt/lists/ | head -n 10
total 153900
drwxr-xr-x 3 root root    12288 Sep 22 04:43 .
drwx------ 2 _apt root    12288 Sep 22 04:43 partial
-rw-r--r-- 1 root root   102130 Sep 22 03:49 security.ubuntu.com_ubuntu_dists_xenial-security_InRelease
-rw-r--r-- 1 root root   102176 Sep 22 03:49 us.archive.ubuntu.com_ubuntu_dists_xenial-backports_InRelease
-rw-r--r-- 1 root root   102128 Sep 22 03:49 us.archive.ubuntu.com_ubuntu_dists_xenial-updates_InRelease
-rw-r--r-- 1 root root  4189255 Sep 22 02:28 us.archive.ubuntu.com_ubuntu_dists_xenial-updates_main_binary-amd64_Packages
-rw-r--r-- 1 root root  3967138 Sep 22 02:28 us.archive.ubuntu.com_ubuntu_dists_xenial-updates_main_binary-i386_Packages
-rw-r--r-- 1 root root  3553982 Sep 22 02:28 us.archive.ubuntu.com_ubuntu_dists_xenial-updates_universe_binary-amd64_Packages
-rw-r--r-- 1 root root  3383908 Sep 22 02:28 us.archive.ubuntu.com_ubuntu_dists_xenial-updates_universe_binary-i386_Packages
[email protected]:~$ ls -la /var/log/unattended-upgrades/*.log
-rw-r--r-- 1 root adm   7508 Sep 20 17:18 /var/log/unattended-upgrades/unattended-upgrades-dpkg.log
-rw-r--r-- 1 root root 15245 Sep 21 06:17 /var/log/unattended-upgrades/unattended-upgrades.log
-rw-r--r-- 1 root root     0 Nov 30  2016 /var/log/unattended-upgrades/unattended-upgrades-shutdown.log
[email protected]:~$ find /etc/cron* -type f | xargs grep apt
/etc/cron.daily/apt-compat:# run. We want to randomize the apt update and unattended-upgrade
/etc/cron.daily/apt-compat:    # laptop check, on_ac_power returns:
/etc/cron.daily/apt-compat:# (some code taken from cron-apt, thanks)
/etc/cron.daily/apt-compat:    eval $(apt-config shell RandomSleep APT::Periodic::RandomSleep)
/etc/cron.daily/apt-compat:exec /usr/lib/apt/apt.systemd.daily