Examine source code of Simple Notes

{
  "manifest_version": 2,
  "name": "Mini Notes",
  "version": "1.0",
  "description": "Quick note-taking extension right in your browser.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png",
      "32": "icon.png"
    }
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "16": "icon.png",
    "32": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{88091e40-be8b-4f8d-ac2b-03b1ec70eb1d}"
    }
  }
}