traceroute(8), tracepath(8), ping(8).
This program has long history. Author of traceroute is Van Jacobson and it first appeared in 1988. This clone is based on a port of traceroute to IPv6 published in NRL IPv6 distribution in 1996. In turn, it was ported to Linux by Pedro Roque. After this it was kept in sync by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>. And eventually entered iputils package.
tracepath6 requires CAP_NET_RAW capability to be executed. It is safe to be used as set-uid root.
traceroute6 is part of iputils package.