If you perform a tactical analysis under ChessBase 17, the program automatically inserts variants and comments into the notation during the analysis.
The meaning of most entries, e.g. references to comparative games, innovations, position evaluation by the currently loaded chess engine, etc. are largely self-explanatory.
What is the meaning of the numbers, e.g. (20) in the game example in the references comment. E.g. before the player name Koelln?
This commenting option has existed within ChessBase for many years, so it has primarily nothing to do with tactical analysis. The tactical analysis uses this option for commenting.
Specifically, the user is offered direct information on the given comparison game. The linked game ended in a draw after 20 moves.
