Ignition Damping Box needed?

I was just looking on the internet and found a ultralight website with alot of rotax engine specs. In there diagrams they have a ignition damping box hooked up to the generator coil wires going to the ignition coils. Was wondering if this is just a ultralight thing or if all 503 rotaxs should have one?

this could be related to my previous post about my voltage regulators, but for the sake of fourm norms I didn't want to have two topics in one post.