/usr/bin/swipl is in swi-prolog-nox 7.6.4+dfsg-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/swi-prolog/bin/amd64/swipl
/usr/bin/../lib/swi-prolog/bin/amd64/swipl