Maybe it’s not always needed but because Kirby have a whole lot of own options I usually prefix my options like this:
c::get('plugin.mix.manifest.path');
The Kirby options seems to be growing all the time and it can be hard to predict what is coming next.
Sometime I suggested that Kirby should use a prefix instead like kirby.css.handler instead of css.handler but I got voted down on that one.