pgAdmin 4 is an Open Source administration and development GUI for PostgreSQL.
pgAdmin 4 is a complete rewrite of pgAdmin 3.
pgAdmin4 is cross platform (i.e., Linux, FreeBSD, Solaris, macOS and Windows) and supports PostgreSQL v9.2 and above.
It is available as separate download https://www.pgadmin.org/, but also included in PostgreSQL https://www.postgresql.org/.