Basically what this feature would do is it would allow you to put the replaymod.jar file into your forge server.
Then as you run the server the replay mod makes a dummy user that films the whole server.
After some time / the server shutting down. It outputs a replay file into a specific folder.
Then the server owner runs that replay in the client version and does whatever they want with it.
I'm not so good when it comes to coding, but I tried a bit of modding and I know that the capabilities should be there to do something like this.