What is a postgres superuser

Question

I couldn't find the answer in the docs, what exactly is a superuser in postgres?

Does the superuser have all privileges? Is it per database? Per instance?

Answer 1

https://www.postgresql.org/docs/current/static/sql-createrole.html

These clauses determine whether the new role is a "superuser", who can override all access restrictions within the database.

yes - all privileges in all databases on the specified cluster

Answer 2

A superuser in PostgreSQL is a user who bypasses all permission checks.

Superusers can run commands that can destabilize or crash the database server (e.g., create C functions) and access the operating system.