.GF File Extension
File TypeMETAFONT Bitmap File
What is a GF file?
Font file generated by TeX typesetting applications; saves the bitmap representation of a font that was originally in the equation-based METAFONT .MF format; used for generating glyphs (characters) into TeX documents as well as printing fonts for document proofs.
GF files often have a corresponding .TFM file that contains size metadata for typesetting the font.