From W3C Wiki
CONSTRUCT * is a suggested shortcut to providing a
CONSTRUCT template that returns every triple involved in the query pattern.
This 2005 DAWG thread discusses potential definitions of
?? Are there any SPARQL implementations for this?
Alan Ruttenberg thinks that this feature needs a different name (he suggested
CONSTRUCT MATCH because it is not based on picking out all the variables from the query pattern in the way that
SELECT * is.