Examine source code of Sticky Sidebar Notes

{
  "manifest_version": 2,
  "name": "Sticky Sidebar Notes",
  "version": "1.0",
  "description": "Floating sticky notes on the side of your browser.",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ab5dfd2c-ddb3-4d22-99ce-312e0910037e}"
    }
  }
}