Examine source code of Spitfire

{
  "theme": {
    "images": {
      "theme_frame": "Spitfire_h.png"
    },
    "colors": {
      "frame": "#cccccc",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Spitfire",
  "manifest_version": 2,
  "description": "Persona-nized from a painting I made earlier this year. It's Supermarine Spitfire, a British WW2 fighter plane."
}