Search notes:

Oracle: DBA_REWRITE_EQUIVALENCES

dba_rewrite_equivalences shows rewrite equivalences. This view comes also in the other three variants user_rewrite_equivalences, all_rewrite_equivalences and cdb_rewrite_equivalences. 
select
   req.owner,
   req.name,
   req.source_stmt,
   req.destination_stmt,
   req.rewrite_mode
from
   dba_rewrite_equivalences req;

See also

data dictionary
Rewrite equivalences are managed with the PL/SQL package dbms_advanced_rewrite.

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