Examine source code of FlipHTML5 PDF Downloader

{
  "icons": {
    "16": "icon16.plasmo.e7bcd3ac.png",
    "32": "icon32.plasmo.ce39377b.png",
    "48": "icon48.plasmo.3c17e113.png",
    "64": "icon64.plasmo.df317abe.png",
    "128": "icon128.plasmo.6a4310c5.png"
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "16": "icon16.plasmo.e7bcd3ac.png",
      "32": "icon32.plasmo.ce39377b.png",
      "48": "icon48.plasmo.3c17e113.png",
      "64": "icon64.plasmo.df317abe.png",
      "128": "icon128.plasmo.6a4310c5.png"
    },
    "default_popup": "popup.html"
  },
  "version": "1.0.9",
  "author": "",
  "name": "FlipHTML5 PDF Downloader",
  "description": "Download FlipHTML5 flipbooks to high-quality PDF. A fast and easy flipbook to PDF converter for offline reading.",
  "background": {
    "scripts": [
      "static/background/index.js"
    ]
  },
  "permissions": [
    "activeTab",
    "storage",
    "https://fliphtml5.com/*",
    "https://online.fliphtml5.com/*",
    "https://*.supabase.co/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://product.extensionkit.cc/auth/callback*"
      ],
      "js": [
        "authCallback.7ecb67eb.js"
      ],
      "run_at": "document_start",
      "css": []
    },
    {
      "matches": [
        "https://fliphtml5.com/*",
        "https://www.fliphtml5.com/*"
      ],
      "js": [
        "pageVisit.33d5d90f.js"
      ],
      "all_frames": false,
      "run_at": "document_idle",
      "css": []
    },
    {
      "matches": [
        "https://online.fliphtml5.com/*"
      ],
      "js": [
        "scanDialog.8c88e9fe.js"
      ],
      "all_frames": false,
      "css": [
        "scanDialog.d4399aab.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "fliphtml5-downloader@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}