Used to allow conditional content construction to be made streamable. Used to avoid outputting an element if it would have no children.
Permitted parent elements: any XSLT element whose content model is sequence-constructor; any literal result element
Element has no attributes
Notes on the Saxon implementation
New in XSLT 3.0, and implemented since Saxon 9.7.
The following code generates a wrapper element for a non-empty sequence,
however it is not guaranteed-streamable because it processes child
event elements more than once:
To make this streamable, it can be rewritten using the