The commands
CREATE_REPLICATION_SLOT
slot_name
LOGICAL options
DROP_REPLICATION_SLOT
slot_name
START_REPLICATION SLOT
slot_name
LOGICAL options
are used to create, drop, and stream changes from a replication slot, respectively. These commands are only available over a replication connection; they cannot be used via SQL. See the section called “Streaming Replication Protocol” for details on these commands.
The command pg_recvlogical(1) can be used to control logical decoding over a streaming replication connection. (It is uses these commands internally.)