LS2-edit currently edits:

Idle speed
Rev Limiters
MAF Table
Hi Octane and Low Octane Timing Tables
Inlet Air Temperature Timing
Maximum Brake Torque timing Table
Injector sizing
Toque Management
PWM Fan Control
VE tables
PE vs RPM
Cat Overtemp
Skip Shift Disable
MAF high THreshold
disabling all the C6 DTC's

THese are all tested features. Some features being tested include

2 Bar MAP sensor
P0101 test parameters
P0068 thresholds