The only third-party library is src/lib/ExtPay.js (ExtensionPay), shipped unmodified and unminified. It handles the Pro licence check against extensionpay.com. Everything else is first-party source, unminified and unbundled: there is no build step that transforms the code, so the ZIP contains exactly the files as written.

The Firefox package uses an event page (background.scripts), not a service worker.

One optional setting hides a promotional banner that Twitch places above the chat ("channel skins"). It is OFF by default and the user has to turn it on; the extension does not block or hide advertising by itself.