I minimalized the file structure and I even eliminated the nav.xhtml and integrated the code into content.xhtml.
At the moment I think, there's no way to enhance the minimalization.
There's no other epub3 in the world, which could beat it
The attached epub3 validates. Please do not open it in Sigil, if you like to look into it, because Sigil will destroy the file structure.
Tomorrow I have to check out, if such a minimal epub3 works with a Kobo.
I will give a feedback here.
content.opf
Code:
<?xml
version= "1.0"
encoding="utf-8"?>
<package
version= "3.0"
unique-identifier="book-id"
xmlns:dc= "http://purl.org/dc/elements/1.1/"
xmlns= "http://www.idpf.org/2007/opf">
<metadata>
<dc:identifier id="book-id"> urn:isbn:978-3-908778-02-8</dc:identifier>
<meta property="dcterms:modified">2017-03-07T12:14:04Z </meta>
<dc:language> de-DE </dc:language>
<dc:title> Tanz der seligen Geister </dc:title>
<dc:creator> Alice Munro </dc:creator> <!-- optional -->
<dc:publisher> Dörlemann </dc:publisher> <!-- optional -->
<dc:date> 2012 </dc:date> <!-- optional -->
</metadata>
<manifest>
<item id="content" href="content.xhtml" media-type="application/xhtml+xml" properties="nav"/>
<item id="cover" href="cover.jpg" media-type="image/jpeg"/>
</manifest>
<spine>
<itemref idref="content"/>
</spine>
</package>
content.xhtml
Code:
...
<h2>Inhaltsverzeichnis</h2>
<nav epub:type="toc">
<ol>
<li><a href="content.xhtml#t1">Der Walker Brothers-Cowboy</a></li>
<li><a href="content.xhtml#t2">Die leuchtenden Häuser</a></li>
<li><a href="content.xhtml#t3">Bilder</a></li>
<li><a href="content.xhtml#t4">Danke für die Schlittenfahrt</a></li>
<li><a href="content.xhtml#t5">Das Büro</a></li>
<li><a href="content.xhtml#t6">Ein Gläschen Medizin</a></li>
<li><a href="content.xhtml#t7">Zur Autorin und zu ihrer Übersetzerin</a></li>
<li><a href="content.xhtml#t8">Zum Buch</a></li>
<li><a href="content.xhtml#t9">Impressum</a></li>
</ol>
</nav>
</body>
</html>