psql & pg_service.conf
functionalImport PostgreSQL connection service files, or export your PostgreSQL connections as one psql and every libpq tool understands.
The PostgreSQL connection service file, described in the PostgreSQL manual under The Connection Service File, gives connections short names that psql, pg_dump and every libpq-based tool understand: psql service=orders. pgAdmin, DBeaver and many drivers read it too, which makes it the closest thing PostgreSQL has to a shared connection list.
# ~/.pg_service.conf [orders] host=pg1.acme.internal port=5432 dbname=orders user=app sslmode=verify-full
From a service file into SQLly
The per-user file is ~/.pg_service.conf (%APPDATA%\postgresql\.pg_service.conf on Windows); a shared one sits in the directory pg_config --sysconfdir prints, and PGSERVICEFILE can point anywhere else. Choose File → Import From Other Tools… and pick it. Each [section] becomes a PostgreSQL connection named after the service, with host (or hostaddr, and localhost when neither is set), port, dbname, user, sslmode, and the sslrootcert, sslcert and sslkey paths. When host lists several hosts, the first one is used. A password line is ignored; keep passwords in your keychain or in ~/.pgpass.
From SQLly into a service file
Choose File → Export for Other Tools → PostgreSQL Service File (pg_service.conf)…. Only PostgreSQL-family connections are listed. Each one becomes a section named after the connection, with spaces and any other character a service name can't hold turned into underscores, and a number added when two names collide. Service files have no folders, so SQLly projects are not written. Append the sections you want to your ~/.pg_service.conf, then connect with psql service=<name>.