gnus-agent-cache

gnus-agent-cache is a variable defined in `gnus.el'.
Its value is

t

Documentation:
Controls use of the agent cache while plugged.
When set, Gnus will prefer using the locally stored content rather
than re-fetching it from the server. You also need to enable
`gnus-agent' for this to have any affect.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.