This attribute may be set on the xsl:source-document instruction to enable line numbering and column numbering for
the document being read. The permitted values are:
If line and column numbering is enabled for a document, the line and column number of an element node in the document can be obtained using the extension functions saxon:line-number and saxon:column-number respectively.
Line numbering of source documents can also be enabled using the configuration option
Feature.LINE_NUMBERING or the command-line
-l (letter ell).
Assuming the XML parser is conformant with the SAX specification, the line and column number reported for an element represent the position of the ">" character at the end of the start tag.