Examine source code of Notepad Popup

{
  "manifest_version": 2,
  "name": "Save and View Notes",
  "description": "__MSG_extensionDescription__",
  "version": "1.0",
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "122.0",
      "id": "{e463d30b-2874-4c23-99fb-75af2ff209f9}"
    }
  },
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_title": "Save and View Notes",
    "default_popup": "pagebar/popup.html"
  },
  "permissions": [
    "storage"
  ]
}