Is this just a soffit wall or something else?

[PugnacAutMortem]

We are doing some renovating and I was looking at expanding our bathroom a bit. I pulled the original floor plan on our house trying to figure out what might be in this soffit wall in our master bath but this is all the plan shows:



The original owners put the optional bath so we have a shower on the far left and a vanity and toilet on the bottom. Any ideas on what they could be running (if anything) in the X area above the tub? Or why they put something like that in the house in the 1st place? My hope is to just get rid of it. Thanks in advance for any ideas!