In my "pg_hba.conf" I have:
local   all             all                                     trust
host    all             all               trust
host    all             all             ::1/128                 trust
Reading some explanation from various web-pages:

A local entry is semantically the same as a host entry. However, you do not need to specify a host that is allowed to connect. The local entry is used for client connections that are initiated from the same machine that the PostgreSQL server is operating on.
I was under impression that:
local all all trust
is for access to all user on a machine on which postgresql is running

But to my surprise I can access my database from other machine on my network and even from another sub-network that I'm connected to via VPN

I'm assessing postgresql database via apache + browser (using sql-ledger program).

How this authentication/access works?