Examine source code of Action Creator for Nirvana

{
  "manifest_version": 2,
  "name": "Action Creator for Nirvana",
  "version": "1.3.1resigned1",
  "description": "The 'Action Creator for Nirvana' addon for Firefox lets you add new actions to your inbox of Nirvana for GTD® (nirvanahq.com) without opening the web-client. If you enter your email and password, the Nirvana API it used. Otherwise - or when you typed wrong credentials - the functionality to create actions via mail is used. Therefore you need to enter the nirvana inbox mail. The addon is not affiliated with or created by Nirvana.",
  "icons": {
    "16": "images/action-creator-for-nirvana-16.png",
    "32": "images/action-creator-for-nirvana-32.png",
    "48": "images/action-creator-for-nirvana-48.png"
  },
  "browser_action": {
    "default_icon": "images/action-creator-for-nirvana-32.png",
    "default_title": "Action Creator for Nirvana"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "storage"
  ],
  "options_ui": {
    "page": "options/options.html"
  },
  "applications": {
    "gecko": {
      "id": "action-creator-for-nirvana@jonas-hellmann.de"
    }
  }
}