[pietvo]

Originally Posted by Valloric

Tidy probably removed it on load, and for good reason since it contained HTML code.

But it will still be in the ePub file on disk.
The following code:

  <style type="text/css">
/*<![CDATA[*/
  <link rel="stylesheet" type="text/css" href="../Styles/StyleNovel.css"/>
  /*]]>*/
  </style>

according to the XML definition should be equivalent to:

  <style type="text/css">
/**/
  &lt;link rel="stylesheet" type="text/css" href="../Styles/StyleNovel.css"/&gt;
  /**/
  </style>

which is quite different from what Sigil shows and apparently interprets. Of course the code above is nonsense.