Detemine name of replication schema

I tried searching the archive for a similar question, but found none.

I am interested in knowing what query can be used to determine the name
of the replication schema(s) installed.

As pgadmin is "aware" of the replication schema(s), as the are listed
for each database
eg: <dbname>
Casts
Languages
Schemas
Replication

I am curious as to what function or sql query is used to obtain that
information?

IOW, I am looking for a generic way to get the names of all replication
schemas in a cluster.

Thank you in advance,

Melvin Davidson