Examine source code of Stylish Reader

{
  "manifest_version": 2,
  "name": "Stylish Reader",
  "description": "Help you learn English better and easier.",
  "developer": {
    "name": "Toly Feng",
    "url": "https://stylishreader.com"
  },
  "version": "0.0.30",
  "icons": {
    "48": "icons/stylish-reader-48.png"
  },
  "background": {
    "scripts": [
      "background_script.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js",
        "assets/js/plyr.js"
      ],
      "css": [
        "assets/css/plyr.css"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    "assets/stylish-reader-48.png",
    "assets/right-arrow.png",
    "assets/cancel-button.png",
    "popup/dist/*"
  ],
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "webRequest",
    "webNavigation",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "browser_action": {
    "default_icon": {
      "48": "icons/stylish-reader-48.png",
      "96": "icons/stylish-reader-48.png"
    },
    "default_title": "Stylish Reader",
    "default_popup": "popup/dist/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6ecd6bf3-258a-4d85-a021-ea855c91d9cb}"
    }
  }
}