pgpool2 vs postgresql-9.4-pgpool2

hello,

My OS Platform is Jessie.
I am studying pgpool2 , but I am confused .
Could you please tell me the differences between the following 2
packages.

pgpool2/stable 3.3.4-1 amd64
connection pool server and replication proxy for PostgreSQL

postgresql-9.4-pgpool2/stable 3.3.4-1 amd64
connection pool server and replication proxy for PostgreSQL - modules

apt show pgpool2/stable 3.3.4-1 amd64 output :

Description: connection pool server and replication proxy for PostgreSQL
pgpool-II is a middleware that works between PostgreSQL servers and a
PostgreSQL database client. It provides the following features:
.
* Connection Pooling
* Replication
* Load Balance
* Limiting Exceeding Connections
* Parallel Query
.
pgpool-II talks PostgreSQL's backend and frontend protocol, and relays a
connection between them. Therefore, a database application (frontend)
thinks
that pgpool-II is the actual PostgreSQL server, and the server (backend)
sees
pgpool-II as one of its clients. Because pgpool-II is transparent to both
the
server and the client, an existing database application can be used with
pgpool-II almost without a change to its sources.
.
This is version 3 of pgpool-II, the second generation of pgpool.

apt show postgresql-9.4-pgpool2/stable 3.3.4-1 amd64 output :
Description: connection pool server and replication proxy for PostgreSQL -
modules
pgpool-II is a middleware that works between PostgreSQL servers and a
PostgreSQL database client. This package contains support modules for
the PostgreSQL 9.4 server:
.
* pgpool_adm
* pgpool_recovery (PostgreSQL 9.1 and above)
* pgpool_regclass (PostgreSQL 9.1 and above)

Thank you.

Best Regards,
Steven