I downloaded the file from http://www.yqcomputer.com/
and received an Installer .mpkg.
I installed this, and contrary to the description on the above page,
there is no /usr/local/bin/swipl
So, I have no idea what to do next. Unfortunately, there is also no
README or INSTALL text file describing e.g., how to launch the prolog
system with X11 on MacOS.
Any pointers are welcome.