compatibility characters (in XML context)

[Alexandre Arcouteil]

This is a beginner question :

In the XML 1.1 Proposed Recommendation 05 November 2003 
(http://www.w3.org/TR/xml11), it is said that "Document authors are 
encouraged to avoid "compatibility characters", as defined in section 
6.8 of [Unicode]" so relating to Unicode 2.0.

I don't see any online documentation about explicit definition of 
"compatibility characters" according to 2.0.

At least I'd like to know if characters like "Ã" "Ã" or "Å" are 
concerned. Is somewhere a complete chart of "compatibility characters" ?

Thanks for explanations