Indentation should consist of 4 spaces. Tabs are not allowed.
Tags which are at the same level must have the same indentation.
<sect1> </sect1> <sect1> </sect1>
Tags which are one level under the previous tag must be indented with 4 additional spaces.
<sect1>
<sect2>
</sect2>
</sect1>
Multiple block tags within the same line are not allowed; multiple inline tags are allowed, however.
<!-- NOT ALLOWED: -->
<sect1><sect2>
</sect2></sect1>
<!-- ALLOWED -->
<para>
<classname>Zend_Magic</classname> does not exist. <classname>Zend_Acl</classname> does.
</para>