As best I can tell, netmask does only one small thing:
Shows the netmask for target addresses, either locally or in The Great Beyond.
I see that it has a few options to it, for showing results in a variety of formats. I’m sure one will fit your needs.
Try as I might, I don’t see where it does much else. Perhaps it is complete in its simplicity … ? 😕
Regardless, I’m sure someone will clue me in, if I’ve overlooked netmask’s grandest feat. 😐