Given the excessively technical description in the old mdoc_samples(7)

Given the excessively technical description in the old mdoc_samples(7)
manual and its successor groff_mdoc(7), i always considered .Ql as
purely physical markup, but it turns out describing it better allows
to give it a semantic meaning (in-line literal display) that doesn't
contradict existing usage.  One less physical, one more semantic
macro, yay!

Found in a discussion with Steffen Nurpmeso <sdaoden at yandex dot com>.