so little more detail here, in real oracle database I have column:
NUMBER with no precision specified
I reverse it back (its oracle 11G), I use ojdbc8.jar as JDBC driver.
On reversed model I get NUMERIC 0. (physical diagram in VP)
When I generate DDL:
Postgres - I get numeric(19, -127)
Oracle - I get as well number(19, -127)
Also in your supported list you mention Oracle 9/10, but there is out there 11g, 12c and 18 version of Oracle, looks to me like you are a bit behind a reality with support. And as I mentioned earlier, data mapping is related to specific version of any database engine, its another dimension in configuration.