Comment # 7 on bug 1127766 from Olaf Hering

0:esprimo:~ # cat /mnt/etc/snapper/configs/root 

# subvolume to snapshot
SUBVOLUME="/"

# filesystem type
FSTYPE="btrfs"

# users and groups allowed to work with config
ALLOW_USERS=""
ALLOW_GROUPS=""

# start comparing pre- and post-snapshot in background after creating
# post-snapshot
BACKGROUND_COMPARISON="yes"


# run daily number cleanup
NUMBER_CLEANUP="yes"

# limit for number cleanup
NUMBER_MIN_AGE="1800"
NUMBER_LIMIT="50"


# create hourly snapshots
TIMELINE_CREATE="yes"

# cleanup hourly snapshots after some time
TIMELINE_CLEANUP="yes"

# limits for timeline cleanup
TIMELINE_MIN_AGE="1800"
TIMELINE_LIMIT_HOURLY="10"
TIMELINE_LIMIT_DAILY="10"
TIMELINE_LIMIT_MONTHLY="10"
TIMELINE_LIMIT_YEARLY="10"


# cleanup empty pre-post-pairs
EMPTY_PRE_POST_CLEANUP="yes"

# limits for empty pre-post-pair cleanup
EMPTY_PRE_POST_MIN_AGE="1800"

0:esprimo:~ # ls -l /mnt/etc/snapper/configs/root 
-rw-r--r-- 1 root root 800 Mar 22  2016 /mnt/etc/snapper/configs/root

I'm sure I never used snapper, perhaps a config as included in earlier pkgs?