Postgres allows for an "application name" to be used when connecting to the database, this allows the tools such as pg_stat_activity to display who is using any of the resources on the database.

Currently the URIs allowed in the connection string according to master (https://git.zabbix.com/projects/AP/repos/postgresql/browse/README.md) don't allow setting the application name.

It would be a very welcomed modifcation that the postgres agent identified itself with something significative or that the field could be part of the customization options such as the user or password

This is the reference from postgres here