/lib/udev/rules.d/40-timer-permissions.rules is in ubuntustudio-default-settings 0.54.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | # make precisian timers accessable to audio group and MIDI
#
# created Sep 3 2012
KERNEL=="rtc0", GROUP="audio"
KERNEL=="hpet", GROUP="audio"
|