Examine source code of The Simple Lighthouse.

{
  "theme": {
    "images": {
      "theme_frame": "LighthouseHeader.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "The Simple Lighthouse.",
  "manifest_version": 2,
  "description": "I will place more concern on how firefox crops the images next time. O_o"
}