Anyone can explain the concept of "System Level Applications"? An example?
It's unlikely you'll find a precise definition. In my own experience it's
really a vague term that historically refers to a (usually non-GUI)
application that works close[r] to the operating system (OS). "System" in
this context therefore (usually) refers to the "system" in operating
"system". IOW, if your application works close to the OS itself (using
low-level APIs to conduct its work), it could be referred to as a "system
level application". I don't believe it's an official term however, just a
very general one that can't be precisely qualified (i.e., there's no exact
definition of what constitutes a system level application - if your app is
perceived as doing a lot of "low-level" work then it would qualify but it's
really a personal judgment call).