They are constants. I think they are linked to global.FirstCharacter and global.SecondCharacter. Look in the creation event of objGlobalController its all there.
I'll go ahead and explain that you can define constants under Resources<Define Constant Menu. You'll see a lot of constants. Constants are great because they are easier to remember than a value. Plus I understand they run faster too.
You will see lots of constants there, specifically a lot that start with consAction. These control what state a character is in when they are assigned to the character's Action variable. So Action = consActionJuming sets sonic in his Jumping state and runs the corresponding script scrPlayerActionJumping(). All of the code for that is found within the step event of objPlayer under Action Management.
Coolio.
EDIT: Current mockup of new HUD... Well, not really a mockup, but a picture showing off the graphics and where all the graphics will be placed. Had to resize graphics to fit 320x240 box. Actual graphics may or may not be final.