Is SIGQUIT the same as SIGTERM?

No, they're not the same. The default action for both is to terminate the process, but SIGQUIT also dumps core. See e.g. the Linux man page signal(7). kill by default sends SIGTERM, so I can only imagine that the mention of SIGQUIT being default is indeed just a mistake. That default is in POSIX, and so are the numbers for SIGTERM, SIGKILL and SIGQUIT.