Live Stream Repeater and Caching

I was wondering where I can find more information about the details of how live stream repeaters work. After reading through the documentation, I do not fully understand what level of “caching” gets implemented through this set up.

If I am understanding correctly, the purpose of the live repeater is that an edge server will establish only a single connection to an origin server, and then stream that data to all clients connected to the edge server. This being the case, does the edge server perform any type of caching, or is it actually just passing the data through?