Help with extracting .dat Bandai Namco Go Vacation Switch

[Slycer]

Hey, i've extracted the RomFS of Go Vacation Switch from Bandai Namco, and i'm getting multiple .dat files :
RIZ.dat
SHD.dat etc
here's what it looks like in HxD


if someone could tell me more info about this on how i could extract it.
if you need more info just tell me

 

[FAST6191]

Trouble with start of files is they are often radically different to the rest of it.

However the FRES and FSKA are what would be called magic stamps in most things. I do also see D0 at 20 which could be coincidence but also is where FSKA starts. I would usually then make a list of various magic stamps and see if I can match them to any pointers (usually values that count upwards, but could also be file/section sizes).