Then intention of the Arch post-install script is good (that is,
informing the user) but I find the implementation brittle: if the
messages are too many or too long, it can be very easy to miss a
message.

Furthermore, the script cannot be triggered out-of-install, which means
that once the shell session is gone, the information is gone.  (It's
still in the log but it's not so convenient to read and you must know
what you are looking for in advance.)

--
Pierre Neidhardt