Starts with double slash

Starting the match attribute of xsl:template with // forces the processor to scan the entire document tree, which is expensive and rarely necessary.

Incorrect:

<xsl:template match="//item">
  <xsl:value-of select="."/>
</xsl:template>

Correct:

<xsl:template match="item">
  <xsl:value-of select="."/>
</xsl:template>