Certain ports require groff because that's what their manpages are written for. If I understand it correctly, the original manpages get preformated with groff, installed into the .../cat/ directotries, and that's what the user sees eventually.
I haven't found the time yet to look into the internals of the mdoc(7) vs man(7) markup, but would it make sense to try to slightly rewrite the original manpages to get rid of groff? Is that generally possible? Is an mdoc(7) manpage, when written with compatibility in mind, acceptable for upstream that originaly wrote the manpage for groff?
