What is the difference between these two "special colors" ?

[LaurentG]

I incidently discovered that the background color 254,254,254 in a style is not a light blank... but "random" color, that changes each time it is applied.
Interresting feature.... nowhere documented, if I'm not wrong....

But I then also discovered it's also the case of colour 253,253,253

These two colours are not show the same way in "pick color" applet of style definition.

My Question : Are these two "special colors" identical, and if ot (what I strongly believe !) what are the differences in behaviour between choosing one or the other
And are there other "special colors" ?

[AdminAdmin]

They were part of something which I added many years back, and although I've remove the UI for them the functionality does remain.  To that end, I suppose they are secret(ish).  I thought there was some reference to them somewhere in docs, but I can't see it now.

They are the only two, the one on the left means "pick a completely random colour", the one on the right means "pick a random colour from this set of colours".

Tom