We have been using AT-TLS for quite a while. We started testing IMS Connect and one of the migration/configuration steps is:
Release : 16.0
Component : CA ACF2 for z/OS
ACF2 provides default (internal) CLASMAP records to specify the 3 character ACF2 resource type code.
The ACF2 default for SERVAUTH can be seen by issuing ACF command 'SHOW CLASSMAP':
******** SERVAUTH SER 64 558