Where is my TNSNAMES.ORA from Oracle database 21c

Oracle has started from Oracle version 18c to use Oracle read-only software trees. See my blog Configuring Read Only OracleHome - 18c 

From Oracle version 21c there are no distinctions between software trees in read-only and read-write modes. As of now, the default configuration is set to utilize the read-only mode introduced in Oracle 18c.

When installing a CDB through DBCA on Oracle Database 21c, you will observe the presence of TNSNAMES.ORA. 

The question then arises: where is it located?