9.18.5 Store arbitrary data

The registry has a simple API that uses a Message-ID as the key to store arbitrary data (as long as it can be converted to a list for storage).

Function: gnus-registry-set-id-key (id key value)

Store value under key for message id.

Function: gnus-registry-get-id-key (id key)

Get the data under key for message id.

Variable: gnus-registry-extra-entries-precious

If any extra entries are precious, their presence will make the registry keep the whole entry forever, even if there are no groups for the Message-ID and if the size limit of the registry is reached. By default this is just (marks) so the custom registry marks are precious.