Just noticed the Setting up Identity Data Stores chapter still mentions db (I had some feedback on a KB which did the same!)
Noticed it in 2 places, but worth checking the rest of it:
1st sentence under Introducing Identity Data Stores:
An identity data store, or an identity repository, is a persistent repository of user data, for example, a directory server, an LDAP, a database, and others.
Under step 3 in To Configure an Identity Data Store:
Most data stores are directory services, though the Database Repository lets you connect to an SQL database through JDBC.