YAM .folders structure

I was able to completely mix up my folders and foldergroupstructure as refelcted in the .folders file.
As it was a lengthy structure i wanted to make it more hiërarchical using the normal copy& paste MUI interface. I got however strange copy effect that seem not easy to undo.
Is doing it manuaaly possible?

What do the hexadecimal figures refer to as in this piece ?

YFO3 - YAM Folders
@FOLDER Incoming
Incoming
d72f3de2
@ENDFOLDER
@FOLDER Sent
Sent
d7b374f5
@ENDFOLDER
@FOLDER YAM8Problems
YAM8Problems
5aabaf0a
@ENDFOLDER
@FOLDER Test3
Test3
d40e38c2
@ENDFOLDER