@TL2 - the tables referenced in the help UN_<ID>_ASSOCIATIONS, UN_<ID>_RULES and UN_<ID>_SUBNETWORKS are for ArcGIS Pro 2.7 and higher versions if I'm reading the documentation correctly.
The repository tables that implement GDB replication are tracked in the database are the following tables: the GDB_ITEMS, GDB_ITEMRELATIONSHIPS, GDB_ITEMTYPES, and GDB_REPLICALOG. The ArcMap help documentation has a much better description of these tables and can be referenced here.
Lastly, I'm thinking the Global ID's created in preparation for GDB replication are what are used in the various repository tables to track all kinds of replication behavior. To my knowledge, there are no other tables created for this behavior.