Examine source code of Goodreads Downloader

{
  "manifest_version": 2,
  "name": "Goodreads Downloader",
  "version": "1.2",
  "description": "Adds a 'Download' button to Goodreads and auto-downloads EPUB from OceanOfPDF",
  "content_scripts": [
    {
      "matches": [
        "*://www.goodreads.com/*",
        "*://goodreads.com/*"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_idle"
    },
    {
      "matches": [
        "*://oceanofpdf.com/*",
        "*://*.oceanofpdf.com/*"
      ],
      "js": [
        "oceanContentScript.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{42ae7f13-4978-4173-ae25-1c784be3cfdd}"
    }
  }
}