man.hyphenate.filenames — Hyphenate filenames?
If zero (the default), hyphenation is suppressed for
man.hyphenate.filenames is non-zero,
filenames will not be treated specially and are subject to hyphenation
just like other words.
If you are thinking about setting a non-zero value for
man.hyphenate.filenames in order to make long
filenames/pathnames break across lines, you'd probably be better off
experimenting with setting the
man.break.after.slash parameter first. That
will cause long pathnames to be broken after slashes.