Renoise 3 XRNS what and how are things saved?

I have question about ogg sample compression in song, just like in Hunz xrns-s.

https://forum.renoise.com/t/hunz-album-xrns-files/29733

How the song files where prepared in terms of sample file format? I am asking because when i open them and save without any changes the file size gets much larger.