The depth of the index tree.
- if 1, there are no PMGI chunks, only PMGL chunks.
- if 2, there is 1 PMGI chunk. All chunk indices point to PMGL chunks.
- if 3, the root PMGI chunk points to secondary PMGI chunks, which in turn point to PMGL chunks.
- and so on...
Definition at line 1257 of file mspack.h.