apt-check is part of update-notifier. That said, this does not seem to be hooked into apt, at least in 18.04. Does
grep -R apt-check /etc tell you anything? ** Package changed: apt (Ubuntu) => update-notifier (Ubuntu) ** Changed in: update-notifier (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1781772 Title: apt-get update runs apt-check at nice 19 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/update-notifier/+bug/1781772/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs