Question about rocket chat apps

Hello everyone,

I am new to the whole rocket chat topic. I deployed Rocket chat through the official instructions to deploy rocket chat in a docker container.
Now I want to know how it’s behave if I install apps, especially jitsi.
Does then everything run locally or I am connecting than to the public jitsi servers?

The setup should be for me and my family.
I also asked this on Reddit but I got different answers:

It would be great to get a clear answer if this runs than locally or via public servers for jitsi and maybe other applications.
Especially for new users like me, it would be very helpful. Thank you very much.