Man pages matching name dwfilter in section 1:

dwfilter.1.en	debian 10 / dwdiff
dwfilter.1.nl	debian 10 / dwdiff
dwfilter.1.en	debian 11 / dwdiff
dwfilter.1.nl	debian 11 / dwdiff
dwfilter.1.en	debian 12 / dwdiff
dwfilter.1.nl	debian 12 / dwdiff