json-to-xml namespace

Hi,

I am a little puzzled as I convert some json to xml, the json-to-xml
function seems to put the resulting xml in the
http://www.w3.org/2005/xpath-functions namespace, as specified on its root
element.
This root element has local-name() "map". xslt maps are functions, but this
is an element not an xslt map.
Why is this in a namespace?
What am I missing

Thank you.
Regards.
ac