$ systemctl status systemd-udev-settle
● systemd-udev-settle.service - udev Wait for Complete Device Initialization
   Loaded: loaded (/usr/lib/systemd/system/systemd-udev-settle.service; static; vendor preset: disabled)

$ systemctl --reverse list-dependencies systemd-udev-settle.service
systemd-udev-settle.service
● └─dmraid-activation.service

$ systemctl cat dmraid-activation.service
# /usr/lib/systemd/system/dmraid-activation.service
[Unit]
Description=Activation of DM RAID sets
DefaultDependencies=no
Conflicts=shutdown.target
After=systemd-udev-settle.service
Before=lvm2-activation-early.service cryptsetup.target local-fs-pre.target shutdown.target
Wants=systemd-udev-settle.service