[iliakan]

I have classes, like this:

<main class="main formatted">
  <div data-trusted="1" class="code-example" data-highlight-block="0-0,3-4">
    <div class="codebox code-example__codebox">
      <div class="codebox__code" data-code="1">
        <pre class="line-numbers language-javascript"><code class="language-javascript">// 1. 
        ...
        </code></pre>
      </div>
    </div>

  </div>
</main>

After ebook-convert, on "processed" stage all classes from "<main>" are removed.
Why?

New class "page" is added to many elements.
Again, why? Couldn't find in sources... Spoils all styles.

<main>
  <div data-trusted="1" class="page" data-highlight-block="0-0,3-4">
    <div class="page">
      <div class="page" data-code="1">
        <pre class="line-numbers"><code class="language-javascript">
        ...
        </code></pre>
      </div>
    </div>

  </div>
</main>