For whatever reason, CWEB 3.0 lost the '\ignorespaces' in the last line
of macro '\N' in June 1993, and 'pwebmac.tex' took that deviation from
there instead of using the code from 'webmac.tex'.  See the bug report
on the 'tex-k' mailing list
https://tug.org/pipermail/tex-k/2021-October/003704.html for details.