+
+LDAP operations, even subtree searches, normally access only one
+database.
+That can be changed by gluing databases together with the
+.B subordinate
+keyword.
+Access controls and some overlays can also involve multiple databases.
+.TP
+.B add_content_acl on | off
+Controls whether Add operations will perform ACL checks on
+the content of the entry being added. This check is off
+by default. See the
+.BR slapd.access (5)
+manual page for more details on ACL requirements for
+Add operations.
+.TP
+.B extra_attrs <attrlist>
+Lists what attributes need to be added to search requests.
+Local storage backends return the entire entry to the frontend.
+The frontend takes care of only returning the requested attributes
+that are allowed by ACLs.
+However, features like access checking and so may need specific
+attributes that are not automatically returned by remote storage
+backends, like proxy backends and so on.
+.B <attrlist>
+is a list of attributes that are needed for internal purposes
+and thus always need to be collected, even when not explicitly
+requested by clients.