Static DATABASE_POSTGRES 

pub static DATABASE_POSTGRES: &str

postgres is always created by initdb when building a PostgreSQL cluster.

From initdb(1):

The postgres database is a default database meant for use by users, utilities and third party applications.

Given that it can be problematic to connect to template0 and template1 – see DATABASE_TEMPLATE1 for an explanation – postgres is a convenient default, hence this library uses postgres as the database from which to perform administrative tasks, for example.

Unfortunately, postgres can be dropped, in which case some of the functionality of this crate will be broken. Ideally we could connect to a PostgreSQL cluster without specifying a database, but that is presently not possible.