A little Xmas bit for you. Working with one of my clients I got the question.
Is there an XSL reference from what Oracle has implemented?
And the answer from development is
For 10gR1, our XSLT 2.0 support was for the spec at that time (working draft dated 11th November 2002). For 10gR2, it was for working draft dated 04 April 2005. There are some limitations documented in the readme.
In XDK 11g XML Parser and XSLT engine we implement the XSLT 2.0 Recommendation.
Oh our BPEL Server uses the XDK which comes with 10gr2, and hence you can read up about it in the XDK home in the Oracle Home directory of SOA Suite.