For bitmap fonts, it seems the only files Godot accepts are the files created specifically using BMFont. Is that the case?
I ask since BMFont is Windows-only. Which I can handle with but it’s not ideal.
I can confirm that the format is from BMFont.
Though I also noticed that on BMFont’s homepage there’s links to third party tools that also export fnt files. Including an [online converter] (requires Flash), an Adobe Air application, and a Java application.