A #gf file extension is related to the MetaFont format developed by Donald Knuth.
#GF file extension - MetaFont font
What is #gf file? How to open #gf files?
File type specification:
The #gf file extension is related to the MetaFont, a programming language used to define vector fonts.
It is also the name of the interpreter that executes Metafont code, generating the bitmap fonts that can be embedded into PostScript, etc.
The #gf file contains font.