Examine source code of Credentials

{
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "19": "icons/19x19.png"
    },
    "default_popup": "popup/popup_credentials.html",
    "default_title": "Credentials"
  },
  "manifest_version": 2,
  "name": "Credentials",
  "version": "2.0",
  "permissions": [
    "tabs",
    "<all_urls>",
    "file://*/*",
    "http://*/*",
    "https://*/*"
  ],
  "description": "Generare p.iva e cf",
  "icons": {
    "48": "icons/48x48.png",
    "96": "icons/96x96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{23aae554-d6b1-4318-bb42-8143308efd61}"
    }
  }
}