most games will run at maybe 45fps
                                         25fps

idk it can be anything, maybe the number of stuff on the screen or the amount of memory loaded?

I think it may be a rating of how well the ROM will play in comparison to the original SNES. Or not. Who knows.

All I know is that it wasn't there in the last official build.

nah if it always stays the same its not that. if it changes constantly like an fps cont would, then it could be a speed promillage yes.