You can’t import any fonts into the Glowforge software. It renders text on cloud servers, and the fonts available are from the Google Fonts library.
There’s no design in the file, just a font definition, so it should appear blank.
Inkscape has an SVG Font Editor panel that you can use to view/edit the glyphs, but AFAIK you have to import this font definition into a program like FontForge to turn it into a font file you can use with the text tool.
Maybe there’s a way to use it directly with the HersheyText extension in Inkscape, but I have never loaded a custom font into that.