Any program (person), that produces man pages, should check its content for
defects by using

groff -mandoc -t -ww -b -z -K utf8 <man page>

  The same goes for man pages that are used as an input.

  For a style guide use

  mandoc -T lint

-.-

  So any generator should check its products with the above mentioned
'groff' and additionally with 'nroff ...'.

  This is just a simple quality control measure.

  The generator may have to be corrected to get a better man page,
the source file may, and any additional file may.

  Common errors:

  Not removing trailing spaces (in in- and output).
  The reason for these trailing spaces should be found and eliminated.

  Not beginning each input sentence
(that is not confined to a markup)
in the first column.
Line length should thus be reduced.

-.-

The difference between the formatted outputs can be seen with:

  nroff -mandoc <file1> > <out1>
  nroff -mandoc <file2> > <out2>
  diff -u <out1> <out2>

and for groff, using

"printf '%s\n%s\n' '.kern 0' '.ss 12 0' | groff -mandoc -Z - "

instead of "nroff -mandoc"

  Add the option "-t", if the file contains a table.

  Read the output of "diff -u" with "less -R" or similar.

-.-.

  If "man" (man-db) is used to check the manual for warnings,
the following must be set:

  The option "-warnings=w"

  The environmental variable:

export MAN_KEEP_STDERR=yes (or any non-empty value)

  or

  (produce only warnings):

export MANROFFOPT="-ww -z"

export MAN_KEEP_STDERR=yes (or any non-empty value)

-.-.

Output from "mandoc -T lint grolbp.1.man": (possibly shortened list)

mandoc: grolbp.1.man:92:2: WARNING: skipping paragraph macro: PP empty
mandoc: grolbp.1.man:102:2: WARNING: skipping paragraph macro: PP empty

-.-.

Output from "test-groff -b -mandoc -rF0 -rHY=0 -K utf8 -t -ww -z ":

troff: backtrace: file '<stdin>':184
troff:<stdin>:184: warning: trailing space in the line
troff: backtrace: file '<stdin>':188
troff:<stdin>:188: warning: trailing space in the line
troff: backtrace: file '<stdin>':189
troff:<stdin>:189: warning: trailing space in the line