Comment 35 for bug 1246664

> Is it normal, that I didn't have the package installed, but the error still occurred and zram0 was visible after 'swapon -s'?

Hi, If you had it installed before then removed it happens, and is also filed in a bug report:
zram-config runs even after uninstalled, needs purge - https://bugs.launchpad.net/ubuntu/+source/zram-config/+bug/1036339

If you didn't have zram-config installed before, or another script meant to load and configure it's behavior… the zram module should not be loaded, nor the zram devices created.