Hi,
Just checking things - I'm not sure where but I think this is just a typo.
Even worse I think I introduced it because its also in the developer API - which is the base for the online document.
So the source code docu talks about 6180 as geodetic datum for EST97 - which matches the EPSG registy org (source of truth for our transformations):
And here EPSG Geodetic Parameter Registry :
You need to select 'Datum' and 'Geodetic datum' in this context to get rid of things that don't matter in this context
And the result:
I assume the documentation on our side is simply wrong in this context - it should be 6180