Log signification

[gilflo]

When starting my game, there's a hundred of similar line on my log that are

Serialization depth limit exceeded at 'ThermalLink'. There may be an object composition cycle in one or more of your serialized classes.

(Filename: Line: 67)

what does it mean?

[Starwaster]

When starting my game, there's a hundred of similar line on my log that are

Serialization depth limit exceeded at 'ThermalLink'. There may be an object composition cycle in one or more of your serialized classes.

(Filename: Line: 67)

what does it mean?

It's an error/warning that is new in recent versions of Unity. The behavior that it is throwing the errors for is not new, just the error reporting. Serialization is where you take some bit of data and turn it the format that it gets stored in memory as.

I wouldn't worry too much about it; I get the same errors even in pure stock KSP and I've seen it in every single log file posted by other players since KSP 1.0