Please Explain This Xml File

[gongpex]

Hello everyone, yesterday I found some xml file from my boss computer, and this the file:

<?xml version="1.0" encoding="UTF-8"?>xsi:schemaLocation="http://www.intershop.com/xml/ns/enfinity/6.4/xcs/impex catalog.xsdhttp://www.intershop.com/xml/ns/enfinity/6.1/core/impex-dt dt.xsd"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://www.intershop.com/xml/ns/enfinity/6.4/xcs/impex"xmlns:xml="http://www.w3.org/XML/1998/namespace"xmlns:dt="http://www.intershop.com/xml/ns/enfinity/6.1/core/impex-dt"major="6" minor="1" family="enfinity" branch="enterprise" build="6.4.0.0.276"><category name="Display-Fixtures-1701" import-mode="UPDATE">  <name>Display-Fixtures-1701</name>  <root>1</root>  <product-assignment-query></product-assignment-query>  <template>category/CatalogCategory</template>  <online>1</online>  <position>1.0</position>  <category-links></category-links>  <display-name xml:lang="en-US">Display Fixtures</display-name>  <description xml:lang="en-US">Display Fixtures</description>  <custom-attributes>	<custom-attribute name="hubert_header_image">/images/level1navigationgraphics/rr_1_2displayfixtures.jpg</custom-attribute>	<custom-attribute name="ShowInMenu" dt:dt="string">True</custom-attribute>	<custom-attribute name="META_KEYWORDS_GENERATE" dt:dt="string" xml:lang="en-US">automatic</custom-attribute>	<custom-attribute name="META_TITLE_GENERATE" dt:dt="string" xml:lang="en-US">automatic</custom-attribute>	<custom-attribute name="META_DESCRIPTION_GENERATE" dt:dt="string" xml:lang="en-US">automatic</custom-attribute>	<custom-attribute name="hubert_featured_products" dt:dt="string"></custom-attribute>	<custom-attribute name="hubert_popularity_rank" dt:dt="string">1</custom-attribute>  </custom-attributes></category>

what mean of xsi and xmlns ? please tell me thanks

[Ingolme]

They have to do with Schema and namespaces