Examine source code of Save to Marvin

{
  "name": "Save to Marvin",
  "version": "1.0",
  "description": "Create a task in Amazing Marvin for the current page",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "savetomarvin@Marvin.com"
    }
  },
  "icons": {
    "16": "images/save-to-marvin-16.png",
    "32": "images/save-to-marvin-32.png",
    "48": "images/save-to-marvin-48.png",
    "128": "images/save-to-marvin-128.png"
  },
  "options_ui": {
    "page": "options.html"
  },
  "manifest_version": 2
}