Examine source code of Read Aloud V2

{
  "manifest_version": 2,
  "name": "Read Aloud V2",
  "version": "1.3",
  "description": "Read selected text aloud using text-to-speech.",
  "permissions": [
    "activeTab",
    "contextMenus",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icons/logo_64.png"
  },
  "icons": {
    "64": "icons/logo_64.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d525705a-85f2-4a3e-a88a-17e7aee82e1d}"
    }
  }
}