Examine source code of Nebular

{
  "theme": {
    "images": {
      "theme_frame": "ffnebulaheader.jpg"
    },
    "colors": {
      "frame": "#a1a1a1",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Nebular",
  "manifest_version": 2,
  "description": "A super cool abstract Firefox Persona that shows the value of space."
}