About Oracle Base Config

In a read-only ORACLE_HOME, the configuration files reside in a location known as ORACLE_BASE_CONFIG.

Starting with Oracle Database 21c, the only available configuration is a read-only ORACLE_HOME where ORACLE_BASE_HOME and ORACLE_BASE_CONFIG are located separately from ORACLE_HOME.

In a read-only ORACLE_HOME, the ORACLE_BASE_CONFIG path is the same as ORACLE_BASE.

ORACLE_BASE_CONFIG\database contains the configuration files for ORACLE_HOME. Each file in the database directory contains ORACLE_SID so that the directory can be shared by many different ORACLE_SIDs.

To print the ORACLE_BASE_CONFIG path, run the orabaseconfig command from the %ORACLE_HOME%\bin directory:
C:\> set ORACLE_HOME=C:\app\oracle\product\21.0.0\dbhome_1
C:\> cd %ORACLE_HOME%\bin
orabaseconfig

For example:

orabaseconfig
C:\> C:\app\oracle

Where, C:\app\oracle is ORACLE_BASE.