Examine source code of Read Aloud: A Text to Speech Voice Reader

{
  "manifest_version": 2,
  "name": "__MSG_extension_name__",
  "short_name": "__MSG_extension_short_name__",
  "description": "__MSG_extension_description__",
  "version": "1.81.1",
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "{ddc62400-f22d-4dd3-8b4a-05837de53c2e}"
    },
    "gecko_android": {}
  },
  "browser_action": {
    "default_area": "navbar",
    "default_icon": "img/icon.png",
    "default_popup": "popup.html?isPopup=1"
  },
  "icons": {
    "16": "img/icon-16.png",
    "48": "img/icon-48.png",
    "128": "img/icon.png"
  },
  "permissions": [
    "activeTab",
    "menus",
    "identity",
    "storage",
    "https://translate.google.com/"
  ],
  "optional_permissions": [
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "http://*/",
    "https://*/",
    "file://*/*"
  ],
  "web_accessible_resources": [
    "js/page/*",
    "img/*",
    "css/*"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "content_scripts": [
    {
      "matches": [
        "https://piper.ttstool.com/"
      ],
      "js": [
        "js/rxjs.umd.min.js",
        "js/messaging.js",
        "js/piper.js"
      ]
    },
    {
      "matches": [
        "https://supertonic.ttstool.com/"
      ],
      "run_at": "document_start",
      "js": [
        "js/rxjs.umd.min.js",
        "js/messaging.js",
        "js/supertonic.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "js/rxjs.umd.min.js",
      "js/peerjs-1.4.7.min.js",
      "js/defaults.js",
      "js/messaging.js",
      "js/google-translate.js",
      "js/tts-engines.js",
      "js/speech.js",
      "js/document.js",
      "js/events.js"
    ],
    "persistent": true
  },
  "options_page": "options.html",
  "options_ui": {
    "page": "options.html",
    "chrome_style": false
  },
  "commands": {
    "_execute_browser_action": {
      "description": "Toggle popup"
    },
    "play": {
      "suggested_key": {
        "default": "Alt+O"
      },
      "description": "Play/Stop"
    },
    "pause": {
      "suggested_key": {
        "default": "Alt+P"
      },
      "description": "Play/Pause"
    },
    "stop": {
      "description": "Stop"
    },
    "forward": {
      "suggested_key": {
        "default": "Alt+Period"
      },
      "description": "Forward"
    },
    "rewind": {
      "suggested_key": {
        "default": "Alt+Comma"
      },
      "description": "Rewind"
    }
  }
}