Saxon

It seems that if you set json-node-output-method="adaptive" on an xsl:output element, Saxon displays an error:

Error in xsl:output/@json-node-output-method on line 3 column 67 of jsonAdaptiveoutput.xsl:
  XTSE0020  Invalid value (adaptive) for serialization method: must be
  xml|html|xhtml|text|json|adaptive, or a QName in 'Q{uri}local' form

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="3.0">
    <xsl:output method="json" json-node-output-method="adaptive"/>
</xsl:stylesheet>

I tested with Saxon 10.8, 11.2, and 11.4