#GF file extension - MetaFont font file
What is #gf file? How to open #gf files?
File type specification:
Metafont is 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 e.g. PostScript. Metafont was devised by Donald Knuth as counterpart to his TeX typesetting system.