Cyrus IMAP 2.5.10 BerkeleyDB use?

[Dan White]

On 02/16/17 16:10 -0600, Kenneth Marshall wrote:
>We are running version cyrus-imapd-2.5.10, and even though no databases
>in imapd.conf default to berkeleydb, something is still using it. Here
>are our database definitions from our imapd.conf:
>
>duplicate_db_path: /dev/shm/cyrus-imapd/duplicate_db
>statuscache_db_path: /dev/shm/cyrus-imapd/statuscache_db
>annotation_db: skiplist
>duplicate_db: skiplist
>mboxkey_db: skiplist
>mboxlist_db: skiplist
>ptscache_db: skiplist
>quota_db: quotalegacy
>seenstate_db: skiplist
>statuscache_db: skiplist
>subscription_db: flat
>tls_sessions_db: skiplist
>userdeny_db: skiplist

In what way is it used?