Till, #2 has the answer to your question. /lib/udev/rules.d/56-hpmud.rules is the relevant file when installed, coming from data/rules/56-hpmud_sysfs.rules in source
** Changed in: hplip (Ubuntu) Status: Incomplete => Triaged -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to hplip in Ubuntu. https://bugs.launchpad.net/bugs/1560388 Title: hpaio entry added automatically to /etc/sane.d/dll.conf Status in HPLIP: New Status in hplip package in Ubuntu: Triaged Bug description: When plugging in my HP Officejet 6210 via USB an entry "hpaio" is added to /etc/sane.d/dll.conf. This breaks scanbd. To manage notifications about this bug go to: https://bugs.launchpad.net/hplip/+bug/1560388/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp