You are looking at the HTML representation of the XML format.
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>
  <query-continue>
    <allpages gapcontinue="Tahače_do_lesa" />
  </query-continue>
  <query>
    <pages>
      <page pageid="90653" ns="0" title="TK po jednání plzeňské krajské rady" contentmodel="wikitext" pagelanguage="cs" touched="2015-10-04T11:44:03Z" lastrevid="97885" counter="426" length="516" new="" />
      <page pageid="93547" ns="0" title="Tabu naší země" contentmodel="wikitext" pagelanguage="cs" touched="2015-09-14T15:59:52Z" lastrevid="100788" counter="504" length="20795" new="" />
      <page pageid="89945" ns="0" title="Tabulky o zákazu vstupu na kůrovce neplatí" contentmodel="wikitext" pagelanguage="cs" touched="2015-10-04T11:44:03Z" lastrevid="97177" counter="269" length="3401" new="" />
      <page pageid="92520" ns="0" title="Tahanice kolem bývalého Vojenského újezdu Dobrá voda znechutí obyvatele" contentmodel="wikitext" pagelanguage="cs" touched="2015-09-14T15:59:52Z" lastrevid="99761" counter="440" length="3761" new="" />
    </pages>
  </query>
</api>