[xsl] I output a tab character, then the output file contains space, tab, space ... why?

["Costello, Roger L. costello@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Folks,

In the below XSLT program I loop over each value in a sequence and separate
the sequence values by a tab (hex 9) character. When I open the output file in
a hex editor I see 3 characters separating the sequence values: space (hex
20), tab (hex 9), and space (hex 20). Why am I getting those space characters?
How do I avoid getting them?  /Roger

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                           version="2.0">

    <xsl:output method="text" />

    <xsl:variable name="headers" select="('A', 'B')"/>
    <xsl:variable name="field-separator" select="codepoints-to-string(9)"/>

    <xsl:template match="/">
        <xsl:for-each select="$headers">
            <xsl:sequence select="." />
            <xsl:sequence select="$field-separator"/>
        </xsl:for-each>
    </xsl:template>

</xsl:stylesheet>