Initial system date and time set by systemd

[Sergei Poselenov <sposelenov@xxxxxxxxxxx>]

Hello all,

Could please someone help me understand, how is the initial date and
time are set on the system?

I have an embedded system with systemd configured as service manager.
Initially, system is not connected to Internet, RTC is not initialized.

When I boot the system, I see:

~# timedatectl 
                      Local time: Tue 2020-07-14 19:19:34 UTC
                  Universal time: Tue 2020-07-14 19:19:34 UTC
                        RTC time: Thu 1970-01-01 02:06:42
                       Time zone: n/a (UTC, +0000)
       System clock synchronized: no
systemd-timesyncd.service active: yes
                 RTC in local TZ: no

Where systemd takes this date "Tue 2020-07-14 19:19:34 UTC"?
There is no previous journal logs in the system, and no
/var/lib/private/systemd/timesync/clock.

Thanks in advance.

(This is a duplicate of 
https://stackoverflow.com/questions/70524544/how-systemd-sets-the-initial-date-on-the-system
)

Regards,
Sergei Poselenov