See Passdb for the list of available drivers.

[wolegis]

https://doc.dovecot.org/2.4.2/core/summaries/settings.html#passdb_driver

and

https://doc.dovecot.org/2.4.2/core/config/auth/passdb.html#passdb_driver

state

See Passdb for the list of available drivers.

But there is no list of drivers on this page. It is very counter-intuitive that the 'list of drivers' can be found below

https://doc.dovecot.org/2.4.2/core/config/auth/passdb.html#success-failure-database

and

https://doc.dovecot.org/2.4.2/core/config/auth/passdb.html#lookup-database

The word driver is not even mentioned there.

Better:

Directly link to a section on https://doc.dovecot.org/2.4.2/core/config/auth/passdb.html named Available drivers listing all drivers (aka databases).

[wolegis]

Same for userdb drivers:

https://doc.dovecot.org/2.4.2/core/config/auth/userdb.html#userdb_driver

and

https://doc.dovecot.org/2.4.2/core/summaries/settings.html#userdb_driver