/usr/bin/xfhelp4 is in xfce4-utils 4.8.3-1ubuntu2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | #!/bin/sh
#
#  xfce
#
#  Copyright (C) 1999 Olivier Fourdan (fourdan@xfce.org)
#  Copyright (C) 2003 Jasper Huijsmans (jasper@xfce.org)
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
HELP_DIR="/usr/share/doc"
if [ ! x"$1" = x"" ]; then
    MODULE="${1%.html}"
else
    MODULE="xfce4-utils"
fi
# Check for translated documentation
if [ -n "$LC_ALL" ] ; then
  LC=$LC_ALL
elif [ -n "$LANG" ] ; then
  LC=$LANG
else
  LC="C"
fi
LC_CLEAN="`echo $LC | sed 's/\(..\)_.*/\1/'`"
if [ -r "$HELP_DIR/$MODULE/html/$LC/index.html" ]
then
  URL="$HELP_DIR/$MODULE/html/$LC/index.html"
elif [ -r "$HELP_DIR/$MODULE/html/$LC_CLEAN/index.html" ]
then
  URL="$HELP_DIR/$MODULE/html/$LC_CLEAN/index.html"
elif [ -r "$HELP_DIR/$MODULE/html/C/index.html" ]
then
  URL="$HELP_DIR/$MODULE/html/C/index.html"
else
  URL="$HELP_DIR/xfce4-utils/html/C/index.html"
fi
xfbrowser4 $URL
 |