On some Husqvarna saws, that grease gun can be used to grease the drive sprocket bearing without having to remove the clutch.Bought Husqvarna 61 brandnew and they sold me one of those little grease guns, never Used it much, a couple years later the dealer that sold it to me advised not using it, said the chances of pumping in dirt out weighs any possible benefit.
Philbert
EDIT: @The Lorax types faster than me!