/etc/blkid.conf is in libblkid1 2.20.1-1ubuntu3.
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 7 8 9 10 | # Perform simple UUID and LABEL lookups using udev information first,
# fall back to scanning if not found
EVALUATE=udev,scan
# Send a change uevent if we discover that a symlink is wrong
SEND_UEVENT=yes
# udev-based systems should not store the cache over a reboot, so we
# place it in /dev
CACHE_FILE=/dev/.blkid.tab
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