The ROM has to be licensed. What will be included depends on that license.
I hope, we will be allowed to put up a github repo containing source code that can be assembled to a complete firmware image (hopefully together with a test-suite that shows if a change/extension to the firmware "behaves well").
I'd also like to add a few gimmicks to the C64-mode as well, like some way to show a directory without losing your program. (Right now, I favor a load"$",8,1 will be hijacked and prints out the directory right after writing "loading". I've seen this in one of the many modified kernals for the C64.)