Examine source code of Greenday Theme2

{
  "theme": {
    "images": {
      "theme_frame": "firefoxtheme.jpg"
    },
    "colors": {
      "frame": "#140a0a",
      "tab_background_text": "#630b0b"
    }
  },
  "version": "2.0",
  "name": "Greenday Theme2",
  "manifest_version": 2,
  "description": "Greenday"
}