exsl:node-set() returns a node-set from a result tree fragment, which is what you get when you look at the
xsl:variable instead of its select attribute to fetch a variable's value. This lets you process the XML created within a variable to process it in multiple steps.
You can also use
exsl:node-set() to turn strings into text nodes.
The object for which to return the corresponding node-set.
The node-set corresponding to the specified