The biggest takeaway here IMO is that Python breaks the standard contract regarding signals–at least for SIGPIPE. Python should not be catching and throwing an exception for SIGPIPE; it should simply exit immediately, which is literally the default POSIX behaviour... unless a script/program/process specifically installs a signal handler to perform cleanup before exit. Python has some pretty awful behaviours built into it, and this is one of them.

Half of this article is not "How do Unix pipes work", but "how to fix broken SIGPIPE handling in Python".