Questions on TimeShift configuration

Hi,
I have a newly installed Manjaro 21.2.3 with BTRFS, so TimeShift is installed by default.

  1. Few hours after my installation, i installed linux515-headers because it’s required by openrazer-meta.
    I noticed that a new snapshot in TimeShift although normally, snapshots are created automatically with an upgrade.

I have this in pacman.log


[2022-02-09T01:04:03+0100] [ALPM] installed linux515-headers (5.15.19-1)
[2022-02-09T01:04:03+0100] [ALPM] transaction completed
[2022-02-09T01:04:03+0100] [ALPM] running '30-systemd-update.hook'...
[2022-02-09T01:04:03+0100] [ALPM] running '60-depmod.hook'...
[2022-02-09T01:04:13+0100] [ALPM] running '70-dkms-install.hook'...
[2022-02-09T01:04:13+0100] [ALPM-SCRIPTLET] ==> dkms install --no-depmod openrazer-driver/3.2.0 -k 5.15.19-1-MANJARO
[2022-02-09T01:04:20+0100] [ALPM-SCRIPTLET] ==> depmod 5.15.19-1-MANJARO
[2022-02-09T01:07:14+0100] [PACMAN] Running 'pacman -U --noconfirm --config /etc/pacman.conf -- /home/xxxxxx/.cache/yay/openrazer/openrazer-meta-3.2.0-1-any.pkg.tar.zst'
[2022-02-09T01:07:14+0100] [ALPM] running '00-timeshift-autosnap.hook'...
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Using system disk as snapshot device for creating snapshots in BTRFS mode
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Mounted '/dev/sda6' at '/run/timeshift/backup'
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Creating new backup...(BTRFS)
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Saving to device: /dev/sda6, mounted at path: /run/timeshift/backup
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Created directory: /run/timeshift/backup/timeshift-btrfs/snapshots/2022-02-09_01-07-14
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Created subvolume snapshot: /run/timeshift/backup/timeshift-btrfs/snapshots/2022-02-09_01-07-14/@
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Created control file: /run/timeshift/backup/timeshift-btrfs/snapshots/2022-02-09_01-07-14/info.json
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] BTRFS Snapshot saved successfully (0s)
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] Tagged snapshot '2022-02-09_01-07-14': ondemand
[2022-02-09T01:07:14+0100] [ALPM-SCRIPTLET] ------------------------------------------------------------------------------

Is it normal that a snapshot is automatically created in this case ?

  1. Any snapshot created takes only @/ and not /@cache nor /@log, which is fine.
    But could you please tell me where this is defined ?

In my system, i see /usr/share/libalpm/hooks/00-timeshift-autosnap.hook, /etc/timeshift-autosnap.conf, but i can’t see in those files where any particular subvolume is included in the snapshots.
Where is it ?

Thanks in advance