As far as I know that is the GDL version.
Just like Archicad has a new version each year, so does GDL.
It is not always sequential.
Archicad 23 = GDL 40 version 2.300
Archicad 22 = GDL 38 version 2.208
Archicad 21 = GDL 37 version 2.117
Archicad 20 = GDL 36 version 2.01
When you request the version in GDL you will get the decimal number (i.e. 2.300).
I don’t know what the actual version number you show is used for (other than for internal reasons), as it does not seem possible to access it via GDL itself as far as I know.
Barry
Versions 6.5 to 22
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision M6800 - i7 4700MQ @ 2.40GHz, 16GB RAM, AMD FirePro M6100 (2GB), Windows 7 64bit