Why is there xmlns in my html output - html

Question

In the html output file from an XSLT process (using saxon9he), there have been 155 occurrences of xmlns:fn="http://www.w3.org/2005/xpath-functions" inserted into a variety of tr elements
The part of xsl that uses xpath-functions is
<xsl:if test="(string(#hideIfHardwareIs)='') or (not(fn:matches(string($input_doc//inf[#id='5'), string(#hideIfHardwareIs), 'i')))">
unless I am reading it wrong, matches takes 3 arguments, a string, another string and then a flag in which case this is case-insensitive.
What I don't undestand is that the tr elements that are showing up with the xmlns arent close to the portion or xsl that the matches() function is done at.
The XSL file I am working with is 2100 lines and the XML file it parses is 12800 lines. So I don't think I can share it easily. I've inherited this and need to (at this time) maintain it.
What are somethings i can look for within the XSL that would insert the xmlns into the html output?

Answer 1

Those functions do not need to be prefixed.
Remove the xmlns:fn="http://www.w3.org/2005/xpath-functions" from your xsl:stylesheet and remove the fn: prefix from the xpath functions.
Examples:
XML Input
<foo>test</foo>
XSLT 2.0 #1
<xsl:stylesheet version="2.0" xmlns:fn="http://www.w3.org/2005/xpath-functions"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="/*">
<xsl:if test="fn:matches(.,'^t')">
<bar><xsl:value-of select="."/></bar>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
Output
<bar xmlns:fn="http://www.w3.org/2005/xpath-functions">test</bar>
XSLT 2.0 #2
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="/*">
<xsl:if test="matches(.,'^t')">
<bar><xsl:value-of select="."/></bar>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
Output
<bar>test</bar>