Examine source code of Thunder Theme

{
  "theme": {
    "images": {
      "theme_frame": "MozillaThunderTheme-Improved.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#001aff"
    }
  },
  "version": "2.0",
  "name": "Thunder Theme",
  "manifest_version": 2,
  "description": "My first Mozilla Firefox theme - It's a little \"Generic\", but that's because I'm not the best drawer in the world."
}