Want to know which manual describes what you're looking for?
$ man -k any=ulimit
Want to open it right away?
Want to read a manual starting at your tag of interest?
$ man -O tag=ulimit ksh'
Want to find the right manual *and* jump ahaed?
$ man -O tag=ulimit -a -k .=ulimit
Want to avoid redundance but still do lookup, opening and scrolling in one go?
$ man -akOtag .=ulimit
This now works as (I) would expect thanks to Ingo's help: https://cvsweb.openbsd.org/src/usr.bin/mandoc/main.c?rev=1.219&content-type=text/x-cvsweb-markup