in
Schema history for a host with no graph. It keeps stamps and the swept baseline in the JVM, so a declaration can be stamped and compared against its predecessor before there is a database.
There is no in-memory counterpart to the other two graph beans, and that is the honest answer for both. A drift log is a durable record an operator reads days later, and a heap map is not one. An observed-schema source reports what a live graph holds, and a host with no graph has no graph to report on.