The FHS says: /var/cache is intended for cached data from applications. Such data is locally generated as a result of time-consuming I/O or calculation. The application must be able to regenerate or restore the data.
Now I wonder: After removal of e.g. the Portage tree from a system, it is generally not possible to restore it. (It can be refetched, but not to its previous state.) Same is true for distfiles, at least to some degree. They may have vanished upstream or from mirrors. Maybe /var/lib would be a better choice? It would also take care of the issue with fetch-restricted files. Ulrich
