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 @26.470s
└─multi-user.target @26.470s
  └─systemd-user-sessions.service @11.569s +28ms
    └─network.target @11.549s
      └─NetworkManager.service @9.601s +1.947s
        └─dbus.service @8.985s +602ms
          └─basic.target @8.982s
            └─sockets.target @8.982s
              └─snapd.socket @8.981s +1ms
                └─sysinit.target @8.978s
                  └─systemd-update-done.service @8.951s +26ms
                    └─ldconfig.service @7.027s +1.900s
                      └─local-fs.target @6.992s
                        └─run-media-vetheon-92063cbf\x2d37eb\x2d44ad\x2d97c9\x2d93b009a9d1cb.mount @5.154s +1.837s
                          └─[email protected] @4.722s +414ms
                            └─dev-sdb2.device @584542y 2w 2d 20h 1min 48.109s +6.135s