SQL, Postgres OIDs, What are they and why are they useful?

Question

I am looking at some PostgreSQL table creation and I stumbled upon this:

CREATE TABLE (
...
) WITH ( OIDS = FALSE );

I read the documentati

Answer 1

If you still use OID, it would be better to remove the dependency on it, because in recent versions of Postgres it is no longer supported. This can stop (temporarily until you solve it) your migration from version 10 to 12 for example.

See also: https://dev.to/rafaelbernard/postgresql-pgupgrade-from-10-to-12-566i