Who am I? Where am I connected?

LibPQ has various defaults for the host, user, and DB name.
There's also the password file, the service file and service name.
In the example below, I can connect with a "naked" psql invocation.

Once connected, can I find out all aspects of the connection string?
Or where they came from, like a pgpass.conf or service file?

How to get the host, port, db name once connected?
SHOW and pg_settings does not appear to be it, at first glance.

Thanks, --DD

c:\Users\ddevienne>psql
psql (12.1, server 14.2)
WARNING: psql major version 12, server major version 14.
         Some psql features might not work.
WARNING: Console code page (437) differs from Windows code page (1252)
         8-bit characters might not work correctly. See psql reference
         page "Notes for Windows users" for details.
Type "help" for help.

ddevienne=>