Examine source code of Smart Marker

{
  "manifest_version": 2,
  "name": "Smart Marker",
  "version": "1.0.1",
  "description": "A simple extension for highlighting text in web pages.",
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "contextMenus"
  ],
  "browser_action": {
    "default_icon": "icons/icon48.png",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles/highlight-menu.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{bcc73634-42b5-4925-aa91-bd15016824a0}"
    }
  }
}