They are used in transverse 6 speed cars that have a hole bored in the end of the crank but don't have a pilot bearing.
They include:
VW Golf, Jetta, Beetle 2009+ with 2.0 Diesel (TDI) . These are all 6 speed and all have transmission code 02Q
Some European-market cars also use the tool. They were 6 speeds with the transmission codes 02M that may have been imported for 6 speed conversions.
Not applicable to Passat
Audi TT, 1.8 turbo engine, 1998-2006, AWD only. Not applicable to front wheel drive versions.
There may be other late-model applications for the #126.