Examine source code of KDROI

{
  "name": "KDROI – Book Marketing Tools for Authors",
  "description": "KDROI is a time-saving book marketing companion that every author – fiction or non-fiction – should have in their toolbox",
  "version": "2.2.9",
  "author": "OlegWock <olegwock@gmail.com>",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "assets/images/kdroi.png",
    "32": "assets/images/kdroi.png",
    "48": "assets/images/kdroi.png",
    "128": "assets/images/kdroi.png"
  },
  "options_ui": {
    "page": "/pages/options/index.html",
    "open_in_tab": true
  },
  "permissions": [
    "storage",
    "*://www.publishingaltitude.com/*",
    "*://www.kdroi.com/*",
    "*://amzr.kdroi.com/*",
    "*://*.amazon.com/*",
    "*://*.amazon.co.uk/*",
    "*://*.amazon.de/*",
    "*://*.amazon.fr/*",
    "*://*.amazon.ca/*",
    "*://*.amazon.it/*",
    "*://*.amazon.es/*",
    "*://*.amazon.in/*",
    "*://*.amazon.co.jp/*",
    "*://*.amazon.com.au/*",
    "*://*.amazon.com.br/*",
    "*://*.amazon.com.mx/*",
    "*://*.amazon.pl/*",
    "*://s3-us-west-2.amazonaws.com/*",
    "*://docs.google.com/*",
    "*://pretty-hot.com/*",
    "*://itswritenow.com/*",
    "*://www.freestufftimes.com/*",
    "*://megabookdeals.com/*",
    "*://yournewbooks.com/*",
    "*://www.yournewbooks.com/*",
    "*://yournewbooks.lpages.co/*",
    "*://*.choosybookworm.com/*",
    "*://ohfb.wufoo.com/*",
    "*://discountbookman.com/*",
    "*://armadilloebooks.wufoo.com/*",
    "*://book-circle.com/*",
    "*://www.book-circle.com/*",
    "*://ereadergirl.com/*",
    "*://igniteyourbook.com/*",
    "*://freeboostmarketing.com/*",
    "*://indiebookoftheday.com/*",
    "*://www.bookzio.com/*",
    "*://www.ebooklister.net/*",
    "*://freediscountedbooks.com/*",
    "*://bookhearts.com/*",
    "*://awesomegang.com/*",
    "*://ebookasaurus.com/*",
    "*://www.freebooks.com/*",
    "*://ebookshabit.com/*",
    "*://shelfless.org/*",
    "*://www.free99books.com/*",
    "*://free99books.com/*",
    "*://fkbt.com/*",
    "*://ijustread.it/*",
    "*://*.digitalbooktoday.com/*",
    "*://*.bookbongo.com/*",
    "*://*.newfreekindlebooks.com/*",
    "*://*.bookangel.co.uk/*",
    "*://*.readingdeals.com/*",
    "*://*.indiestoday.com/*",
    "*://*.freebooktips.com/*",
    "*://*.freeebooksblog.com/*",
    "*://*.cravebooks.com/*"
  ],
  "optional_permissions": [
    "browsingData"
  ],
  "content_scripts": [
    {
      "js": [
        "/contentscripts/amazon.js"
      ],
      "matches": [
        "*://*.amazon.com/*",
        "*://*.amazon.co.uk/*",
        "*://*.amazon.de/*",
        "*://*.amazon.fr/*",
        "*://*.amazon.ca/*",
        "*://*.amazon.it/*",
        "*://*.amazon.es/*",
        "*://*.amazon.in/*",
        "*://*.amazon.co.jp/*",
        "*://*.amazon.com.au/*",
        "*://*.amazon.com.br/*",
        "*://*.amazon.com.mx/*",
        "*://*.amazon.pl/*"
      ]
    },
    {
      "js": [
        "/contentscripts/iframeHelper.js"
      ],
      "run_at": "document_start",
      "match_about_blank": true,
      "all_frames": true,
      "matches": [
        "*://*.freebooktips.com/*"
      ]
    }
  ],
  "web_accessible_resources": [
    "/assets/*",
    "/chunks/*"
  ],
  "browser_action": {
    "default_icon": {
      "16": "assets/images/kdroi.png",
      "24": "assets/images/kdroi.png",
      "32": "assets/images/kdroi.png"
    },
    "default_title": "KDRoi",
    "default_popup": "/pages/popup/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{de303252-d20b-4b44-9c40-3ab5f217b41d}"
    }
  }
}