matrix sytle decision tables do not have documentation

We need to use matrix style decision table feature of Drools but it does not have any documentation.
Below there exists related files but they are almost useless. If you still support this feature, then it will be great if you can
supply documentation and examples for it.

http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-decisiontables/src/test/resources/data/CustomWorkbook.xls

http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-decisiontables/src/test/java/org/drools/decisiontable/SpreadsheetCompilerUnitTest.java testLoadCustomListener()

http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-decisiontables/src/main/java/org/drools/decisiontable/parser/RuleMatrixSheetListener.