Examine source code of GrayShade

{
  "theme": {
    "images": {
      "theme_frame": "grayshadeheader.PNG"
    },
    "colors": {
      "frame": "#3d3c3c",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "GrayShade",
  "manifest_version": 2,
  "description": "A persona that is gray with a slight gradient."
}