I have some of the same stuff growing in one of my tanks.
Im not sure what it is, I suspect its weeping moss.
I can help with what Im sure it is not.
100% sure its not java, or flame, Christmas or peacock. The individual fronds coming off the ribs are too large and distinct and the shape isn't right
I think you are right it looks like that. I'm going to attach it to some driftwood and see how it grows.