- Cache Clean mode; this value may be one of always, auto, prompt and never.
- always will remove all archives after they have been downloaded while auto
- will only remove things that are no longer downloadable (replaced with a
- new version for instance)
+ Cache Clean mode; this value may be one of always, prompt, auto,
+ pre-auto and never. always and prompt will remove all packages from
+ the cache after upgrading, prompt (the default) does so conditionally.
+ auto removes only those packages which are no longer downloadable
+ (replaced with a new version for instance). pre-auto performs this
+ action before downloading new packages.