<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Google Auth Helper</title>
    <style>
      input#code {
        width: 100%;
      }
    </style>
  </head>
  <body>
    <h1>Google Auth Helper</h1>
    <p>
      Copy the code below and paste it in your console.
    </p>
    <input id="code" type="text" value="">
    <script>

      // Set the given callback code as value in the input.
      let code = window.location.search.replace('?code=', '')
      const el = document.querySelectorAll('#code')[0]
      el.value = code

      // Select the whole value on click in the element.
      el.addEventListener('click', (event) => {
        event.target.select()
      })

    </script>
  </body>
</html>

Add the google auth helper to gh pages.
Add the google auth helper to gh pages.
