Examine source code of Simply Notes

{
  "manifest_version": 2,
  "name": "Simply Notes",
  "description": "Displays a pop-up that lets you take note and is saved for viewing later.",
  "version": "1.0",
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "applications": {
    "gecko": {
      "strict_min_version": "52.0a1"
    }
  },
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_title": "Simply Notes",
    "default_popup": "pagebar/popup.html"
  },
  "permissions": [
    "storage"
  ]
}