As defined in the XSLT specification, in section 2.5 :
An element enables forwards-compatible mode for itself, its attributes, its descendants and their attributes if either it is an xsl:stylesheet element whose version attribute is not equal to 1.0. (...)
(...)
If an element is processed in forwards-compatible mode, then:
- if it is a top-level element and XSLT 1.0 does not allow such elements as top-level elements, then the element must be ignored along with its content.
This document contains the following XSLT stylesheet appended:
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If your browser supports XSLT, and you are reading this document, then your browser ignored a unknown top-element from the xsl stylesheet therefore conforming to rule one of forward compatible processing. Otherwise you would have seen a XSLT processing error.