On Debian Wheezy with KDE. I have a file /etc/apt/apt.conf.d/20noperiodic. APT::Periodic::Update-Package-Lists "0"; APT::Periodic::Download-Upgradeable-Packages "0"; APT::Periodic::AutocleanInterval "0"; APT::Periodic::Unattended-Upgrade "0"; And I can confirm with apt-config dump, that these are set and that apt-get won't automatically update. In Apper settings fetching updates is still set to hourly by default and I believe it is a bug and APT::Periodic::Update-Package-Lists "0"; should be honored.
PackageKit doesn't read that file, as it's an abstraction layer above apt/yum/etc.
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