Examine source code of Daily Sites

{
  "name": "Daily Sites",
  "description": "Daily Sites provides a convenient way to group daily-use sites into a list allowing you to open them all with just one click.",
  "version": "1.0.8resigned1",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "images/icon.png"
  },
  "icons": {
    "128": "images/icon128.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "applications": {
    "gecko": {
      "id": "dailysites@pluraldev.com"
    }
  }
}