Edit: Decided to go ahead and install it. IDK what the developer was talking about, since it wasn't a big deal. I don't even think it restarted Safari. Anyway, the way the developer worded it, I thought I might not be able to use Safari until I did some elaborate fix he posted. Anyway, looks good. Another advantage to being jailbroken. Stick it Apple!
I assume it means that when you turn UAFaker on or off it will kill the process "MobileSafari" if it is running (as indeed it appears to do--try using the SBSettings toggle with MobileSafari open). "Kill" is a technical term for ending a process immediately (as opposed to "terminate," which usually implies that the process is asked to end itself, and which allows the process time to clean up loose ends and close files neatly).