No documentation exists about ecpg ORACLE comptaible mode

Hi.
(CCing Michael Meskes)

One of my customers asked me about what oracle compatibility mode in ecpg means,
and I noticed current documentation does not explain ecpg ORACLE compatible mode  (ecpg -C ORACLE) in detail.
I myself learned the feature of "-C ORACLE"  from regression test (src/interfaces/ecpg/test/compat_oracle) and source
code. 

Is lacking documentation intentional or do commit 3b7ab4380 and 3b9b7516f just forget adding the explanation?

As for as I know, "ecpg -C ORACLE" is written briefly in ecpg command reference and PostgreSQL 11 release note,
but they are not enougn information for users to understand feature of "ecpg -C ORACLE".

https://www.postgresql.org/docs/current/app-ecpg.html

-------------------------------
-C mode
Set a compatibility mode. mode can be INFORMIX, INFORMIX_SE, or ORACLE.
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https://www.postgresql.org/docs/11/release-11.html#id-1.11.6.21.5.9
-------------------------------
Add an ecpg mode to enable Oracle Pro*C-style handling of char arrays.

This mode is enabled with -C.
-------------------------------

On the other hand, informix compatible mode is written in detail.
https://www.postgresql.org/docs/current/ecpg-informix-compat.html

Best regards,
Takeshi Ideriha