xsl:otherwise
Used within an xsl:choose element
                    to indicate the default action to be taken if none of the other choices
                    matches. With XSLT 4.0 syntax enabled, it may
                    also appear within xsl:switch.
Content: sequence-constructor
Permitted parent elements: 
         xsl:choose
      
Attributes
| 
 | 
 | XPath expression. Experimental: available only if XSLT 4.0 constructs are enabled. Provides an alternative way of supplying the return value; if present, the contained sequence constructor must be empty. | 
Saxon availability
Available in XSLT 1.0 and later versions. Available in all Saxon editions. Available for all platforms.
Notes on the Saxon implementation
The select attribute is implemented from Saxon 10, provided syntax extensions are enabled.
Provided that syntax extensions are enabled, Saxon (from 10) allows the xsl:when and
                    xsl:otherwise elements to return a value using a select attribute
                    in place of a contained sequence constructor.
Details
Note that forwards-compatibility mode in previous versions of XSLT does not handle the select
                    attribute particularly well. If an XSLT 3.0 processor encounters an xsl:otherwise
                    instruction with a select attribute, and the instruction
                    has an effective version of 4.0, the select attribute
                    will simply be ignored, which will generally give incorrect results.