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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.
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<?xml version="1.0"?>
<api>
<query-continue>
<allcategories accontinue="Business" />
</query-continue>
<query>
<allcategories>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">1889 births</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">1895 births</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">1904 births</c>
<c size="0" pages="0" files="0" subcats="0" xml:space="preserve">1930s automobiles</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">1948 deaths</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">1966 deaths</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">1974 deaths</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">24 Hours of Le Mans drivers</c>
<c size="1" pages="1" files="0" subcats="0" xml:space="preserve">Bugatti</c>
<c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Bugatti vehicles</c>
</allcategories>
</query>
</api>