* What led up to the situation?

     Checking for defects with a new version

test-[g|n]roff -mandoc -t -K utf8 -rF0 -rHY=0 -ww -z < "man page"

  [Use "groff -e ' $' <file>" to find trailing spaces.]

  ["test-groff" is a script in the repository for "groff"; is not shipped]
(local copy and "troff" slightly changed by me).

  [The fate of "test-nroff" was decided in groff bug #55941.]

   * What was the outcome of this action?


an.tmac:<stdin>:16: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:19: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:22: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:28: style: .BI expects at least 2 arguments, got 1
an.tmac:<stdin>:43: style: .BI expects at least 2 arguments, got 1
troff:<stdin>:53: warning: trailing space in the line
an.tmac:<stdin>:73: style: .BI expects at least 2 arguments, got 1
an.tmac:<stdin>:77: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:80: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:85: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:88: style: .BR expects at least 2 arguments, got 1
an.tmac:<stdin>:104: style: .BI expects at least 2 arguments, got 1
troff:<stdin>:126: warning: trailing space in the line
troff:<stdin>:133: warning: trailing space in the line
troff:<stdin>:136: warning: trailing space in the line
an.tmac:<stdin>:144: style: .BR expects at least 2 arguments, got 1
troff:<stdin>:145: warning: trailing space in the line
an.tmac:<stdin>:158: style: .BI expects at least 2 arguments, got 1
an.tmac:<stdin>:164: style: .BI expects at least 2 arguments, got 1


   * What outcome did you expect instead?

     No output (no warnings).

-.-

  General remarks and further material, if a diff-file exist, are in the
attachments.