amd64\stdschem.gdl

Generic Description Language file

A .gdl file contains printer description data in the Generic Description Language of Windows. GDL extends the GPD format of the universal printer driver Unidrv. The file describes printer features, commands, and automatic configuration data. Printer driver packages ship .gdl files together with their .gpd files. The print system parses the file at driver installation.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.