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HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <compare fromrevid="1" torevid="2" xml:space="preserve">&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Řádka 9:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Řádka 9:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-context'&gt;&lt;div&gt;* [https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce E-mailová konference oznámení MediaWiki]&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-context'&gt;&lt;div&gt;* [https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce E-mailová konference oznámení MediaWiki]&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-context'&gt;&lt;div&gt;* [//www.mediawiki.org/wiki/Localisation#Translation_resources Překlad MediaWiki do vašeho jazyka]&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-context'&gt;&lt;div&gt;* [//www.mediawiki.org/wiki/Localisation#Translation_resources Překlad MediaWiki do vašeho jazyka]&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td class='diff-addedline'&gt;&lt;div&gt;&lt;ins class=&quot;diffchange&quot;&gt;* [//index.php/Portál:něco něco]&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
</compare>
</api>