theming – How do I add a font locally?

The following libraries example has the font being accessed from google and one local.

global:
 js:
 css:
   theme:
      styles/local.css: {attributes: { type: "text/css" }}
      styles/editing.css: {attributes: { type: "text/css" }}
      '//fonts.googleapis.com/css?family=Hind+Guntur': { type: external, minified: true }
      'styles/Raleway-Italic-VariableFont_wght.ttf': {type: "application/octet-stream" }
      'styles/Raleway-VariableFont_wght.ttf': {}

• The font loaded from fonts.googleapis.com loads fine.
• The font with the type application/octet-stream gives Invalid CSS asset type.
• The font without the type gives an error _not loaded because its mime type is not text/css’.

How do I load the font from the libraries file?
Is loading the font from the style sheet the only way?