Examine source code of Deep black

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#262626",
      "tab_background_text": "#b8b8b8"
    }
  },
  "version": "2.0",
  "name": "Deep black",
  "manifest_version": 2,
  "description": "A simple theme for simple people. Let Firefox be a frame for all your internet adventures instead of distracting you from it."
}