Examine source code of Wheels On Roll

{
  "manifest_version": 2,
  "name": "Wheels On Roll",
  "description": "This extension will tell you about cycles",
  "version": "1.1resigned1",
  "browser_action": {
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "popup.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b759f864-9566-4d2f-9e22-d025cd31befe}"
    }
  }
}