The patches to Fmtr achieve the following:

(1)  The few mm macros that switch to nofill mode are now
     recognized.  I am not an mm user, but from the manual
     this should work.

(2)  For both mm and me display macros, Fmtr will now look
     to see if the display is in filled mode, as with:
     .(l F   (me)
     and
     .DS F   (mm)

(3)  All material between preprocessor statements (e. g.
     between .TS and .TE) is in nofill mode, as is all
     material within displays that are nofill.  Requests
     that return to fill mode are ignored if they occur
     within a display or preprocessor material.

(4)  A -b flag has been added to begin each sentence on a
     new line, as recommended by some books.  I feel that
     this defeats the whole idea of having neatly formatted
     text to edit, but then editing is a very personal
     matter.

     As noted at the end of the manual page, the emphasis
has been on making sure that text should not be accidentally
filled.  When in doubt, Fmtr leaves the text as it found it.
The real formatter will make the correct decisions at formatting
time.

     Remember also that Fmtr is not a roff emulator.  It
knows nothing about environments, or indeed about the inner
workings of the macros that it recognizes.  If you have
large amounts of unfilled text in sophisticated macros of
your own, carefully examine the output of Fmtr before
discarding the original.