F125 switch versions

[HPsauce]

As highlighted in Craig's recent thread there are (at least) 2 versions of the F125 switch. An earlier one with a round 8-pin connector and a later one with a more rectangular 10-pin connector, though I think with only 9 pins installed.
Internally they are built very differently but supposedly do exactly the same thing. So why two versions?

As MJ recently said:

Originally Posted by MikkiJayne

There is no change in logic between the two types of F125 and the TCU doesn't care which switch it has.

I'm interested to know (largely an academic question) what the extra wire is for and whether there is actually a sensible mapping between the two so that either type of F125 can be rewired to the alternative plug.

My first guess would be that there's a common shared earth/return wire in the earlier version that is separated in the later one, possibly for compatibility to other vehicles in the VAG stable.
The internal view of the later "tracked" version is fairly simple to understand with a bit of thought and observation, the earlier one would require more dismantling and analysis to comprehend.

Unless someone has already published how it works in some sort of circuit/logic diagram?