The time when unit became active or started is printed after the "@" character.
The time the unit took to start is printed after the "+" character.

graphical.target @2min 24.825s
└─multi-user.target @2min 24.825s
  └─plymouth-quit-wait.service @37.885s +1min 46.940s
    └─systemd-user-sessions.service @37.869s +10ms
      └─remote-fs.target @37.858s
        └─remote-fs-pre.target @37.858s
          └─open-iscsi.service @37.830s +25ms
            └─network-online.target @37.820s
              └─network.target @37.819s
                └─NetworkManager.service @37.695s +124ms
                  └─dbus.service @37.692s
                    └─basic.target @37.688s
                      └─sockets.target @37.688s
                        └─libvirtd-ro.socket @37.688s
                          └─libvirtd.socket @37.686s +1ms
                            └─sysinit.target @37.651s
                              └─snapd.apparmor.service @37.547s +103ms
                                └─apparmor.service @37.394s +149ms
                                  └─local-fs.target @37.394s
                                    └─var-snap-firefox-common-host\x2dhunspell.mount @37.352s +32ms
                                      └─zfs-mount.service @36.330s +923ms
                                        └─zfs-import.target @36.324s
                                          └─zfs-import-cache.service @1.363s +34.950s
                                            └─zfs-load-module.service @534ms +405ms
                                              └─cryptsetup.target @530ms
                                                └─systemd-ask-password-wall.path @310ms
                                                  └─-.mount @283ms
                                                    └─-.slice @283ms