gistfile1.txt

$ systemctl --user daemon-reload                                 
hrehfeld@desktop-dev ~/.config/systemd/user
$ cat mu.service.d/override.conf                                 
[Unit]
After=offlineimap@personal.service

[Install]
RequiredBy=offlineimap@personal.service
hrehfeld@desktop-dev ~/.config/systemd/user
$ systemctl --user list-dependencies offlineimap@personal.service
offlineimap@personal.service
● ├─offlineimap.slice
● └─basic.target
●   ├─paths.target
●   ├─sockets.target
●   │ └─dbus.socket
●   └─timers.target
hrehfeld@desktop-dev ~/.config/systemd/user
$ cat mu.service
[Unit]
Description=Indexing maildir $MAILDIR with mu

[Service]
Type=simple
ExecStart=/usr/bin/mu index -m %h/mail


[Install]
WantedBy=mail.target