Tracking Fields in Chrony

When I study with **chronyc tracking** command I got some fields and I need more description about it.

chronyc tracking
----------------
Reference ID    : B9E84541 (nobody.yourvserver.net)
Stratum         : 3
Ref time (UTC)  : Wed Dec 20 16:15:43 2023
System time     : 0.000761215 seconds slow of NTP time
Last offset     : -0.000511070 seconds
RMS offset      : 0.001488404 seconds
Frequency       : 2.166 ppm fast
Residual freq   : -0.066 ppm
Skew            : 2.884 ppm
Root delay      : 0.041033130 seconds
Root dispersion : 0.004155959 seconds
Update interval : 517.6 seconds
Leap status     : Normal

In the example output above, can you describe and give some more details about **"Stratum** (what is the number of layers here? I'm working on a VM machine), **Skew,Root Delay and Leap"** fields (except man doc)