I don’t think Talk is included in the core package.
But like Larry mentioned, it’s just an app, installs in a minute…
You need to clarify how you plan to use Talk.
What it does really well is one to one conversation between 2 people on the same network.
The moment you start increasing the number of attendees, linking people from homes (behind firewalls/routers, etc.), Talk by itself won’t do. Around 5 users Talk falls apart…
And it gets complicated fast…
There are three levels of “complication” - STUN, TURN and Signaling servers.
STUN is included in Talk setup. Turn can be had with an open-source coTURN server.
Signaling server is the one guaranteeing scalability. And they are not even mutually exclusive…
To get Zoom-like scalability with 10-50 users, you’ll need a dedicated signaling server.
The so-called high-performance backend (HPB) from spreed is now open sourced and you can make it work with Nextcloud Talk. But the know-how is not available from Nextcloud documentation. There are multiple guides how to accomplish that, but the easiest is Hansson’s VM that installs and configures HPB on request during install. It works well…
If you need more than just a basic 1-to-1 communication tool, read this
You can also replace Talk with BBB or Jitsi and install the linking app… Lots of options…