Examine source code of Yellow_Gray

{
  "theme": {
    "images": {
      "theme_frame": "firefox_gray_yellow_v1.jpg"
    },
    "colors": {
      "frame": "#3b3b3b",
      "tab_background_text": "#3b3b3b"
    }
  },
  "version": "2.0",
  "name": "Yellow_Gray",
  "manifest_version": 2,
  "description": "Yellow_Gray 1"
}