haven't done anything with it, just noting that when corrupting this region the dex skin is deleted
if I transplant the data of an active dex skin to another with the data included afterwards, the save file deletes itself, so there's other stuff that has to be overwritten, just like the cgear skin; however I'm not really interested in pursuing this further
I should also mention that Musical data is in the 0x56000~0x76000 region of the save file. Pretty much all the DLC including battle videos is at the end of the save file.
(so far I've seen it as mystery gift -> ??if anything?? -> battle videos -> cgear -> musical -> pdex -> ???)
not really dlc, but another observation
battle competition (wifi/IR tournaments) are in the 0x20100(?)~0x209FF region
it's easy to find this data in the RAM and re-register for a tournament if you un-register via a one byte AR code (not posting that for obvious reasons)