Examine source code of Riegel Test Header

{
  "theme": {
    "images": {
      "theme_frame": "testfirefoxheader.jpg"
    },
    "colors": {
      "frame": "#524e4e",
      "tab_background_text": "#8c1212"
    }
  },
  "version": "2.0",
  "name": "Riegel Test Header",
  "manifest_version": 2,
  "description": "test, random pictures put together"
}