We are trying to track the change to the Grid Coverage specification - they changed coordinate reference systems on us.
In summary, the old specification can be browsed here:
(replace 'opengis' by 'geotools' and you get the current geotools implementation).
The new specification (where we are going) can be browsed here:
We are in the process of performing a refactoring of the code from the old specification (org.geotools.gc) to the new one (org.geotools.GridCoverage).