EMB02
This is somehow beyond MCUXpresso IDE scope. Your question is related with gcc itself.
All the debug level related information is documented here
http://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
I checked there is little information about Level 2. If you have interest, I suggest you contact the gcc team. At the bottom of this page, there is contact.
https://gcc.gnu.org/lists.html
Hope this helps,
Jun Zhang