Applies an XSLT stylesheet to the body of a request or response and replaces the body with the transformation result. Every string-valued Exchange property is passed to the stylesheet as an XSLT parameter of the same name; declare a matching xsl:param in the stylesheet to read it. Set such a property beforehand, e.g. with setProperty. See tutorials/xml/35-XSLT-Transformation-to-json.yaml.
Explanation:
customer2person.xsl declares a matching xsl:param and reads it as $company: