Examine source code of Graysphere

{
  "theme": {
    "images": {
      "theme_frame": "Persona_Header.jpg"
    },
    "colors": {
      "frame": "#999999",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Graysphere",
  "manifest_version": 2,
  "description": "A simple slate gray persona with a bit of gradient.  Clean and unobtrusive"
}