I always used `apt install sipcalc`, that does ipv6 just fine since years. Why another tool?

It always seemed confusing that "sip calc" has nothing to do with SIP whatsoever, but then seeing "ipcalc" it's also quite the generic name and not any better for searching on.

Edit: Was wondering who predates whom. Sipcalc had its last release in 2013; the earliest commit here is from 2015. I guess that settles the matter, don't need to find sipcalc's commit history :D. Anyway, I never noticed bugs in sipcalc and I'm also not missing any new features or anything.