Since the process group is orphaned when the parent terminates, and the process group contains a stopped process, POSIX.1 requires that every process in the newly orphaned process group be sent the hang-up signal (SIGHUP) followed by the continue signal (SIGCONT).
The kernel sends SIGCONT after SIGHUP, but the process is waken up by SIGCONT before acting on SIGHUP. So why doesn't the Linux kernel send SIGCONT before SIGHUP?
Related to but not answered by Does the default action of SIGCONT resume the execution of a stopped process before or after first handling any pending unblocked signals?
I did not answer my question.