SWI-Prolog, up to version 9 or so, had an excellent integrated “Help” documentation. But, this has now been replaced by an online “Help” documentation, accessible only if there is internet connection. Is the change permanent or only temporary? The previous arrangement was so much more convenient.
?? ?- help(Topic). still works AFAIK, be it differently than it used to long ago.
It is far less convenient than the online version IMO. You can also run your own local[host] online version using GitHub - SWI-Prolog/plweb: SWI-Prolog web server sources for www.swi-prolog.org
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