diff --git a/scripts/upower/95-upower-hid.hwdb b/scripts/upower/95-upower-hid.hwdb
index a45706a78e..c37c868a11 100644
--- a/scripts/upower/95-upower-hid.hwdb
+++ b/scripts/upower/95-upower-hid.hwdb
@@ -5,8 +5,15 @@
 # https://github.com/networkupstools/nut/
 #
 # To keep up to date, monitor upstream NUT
-# https://github.com/networkupstools/nut/commits/master/scripts/upower/95-upower-hid.hwdb
+#   https://github.com/networkupstools/nut/commits/master/scripts/upower/95-upower-hid.hwdb
 # or checkout the NUT repository and call 'tools/nut-usbinfo.pl'
+# One or more "match lines" below are used to set a "property" for a device;
+# for more syntax and system installation (and override) notes, see
+#   https://www.freedesktop.org/software/systemd/man/hwdb.html
+# (or equivalent for the version of systemd used in your distribution)
+# Note that "During runtime, only the binary database is used" as compiled
+# from files like this by e.g. `systemctl restart systemd-hwdb-update.service`
+# (if you edit your copy locally or maintain a site-local override file in /etc).
 
 # Hewlett Packard
 usb:v03F0p0001*
diff --git a/tools/nut-usbinfo.pl b/tools/nut-usbinfo.pl
index ae26951941..db4b069fd3 100755
--- a/tools/nut-usbinfo.pl
+++ b/tools/nut-usbinfo.pl
@@ -141,8 +141,15 @@ sub gen_usb_files
 	print $outUPower '# This file was automatically generated by NUT:'."\n";
 	print $outUPower '# https://github.com/networkupstools/nut/'."\n#\n";
 	print $outUPower '# To keep up to date, monitor upstream NUT'."\n";
-	print $outUPower '# https://github.com/networkupstools/nut/commits/master/scripts/upower/95-upower-hid.hwdb'."\n";
+	print $outUPower '#   https://github.com/networkupstools/nut/commits/master/scripts/upower/95-upower-hid.hwdb'."\n";
 	print $outUPower "# or checkout the NUT repository and call 'tools/nut-usbinfo.pl'\n";
+	print $outUPower '# One or more "match lines" below are used to set a "property" for a device;'."\n";
+	print $outUPower '# for more syntax and system installation (and override) notes, see'."\n";
+	print $outUPower '#   https://www.freedesktop.org/software/systemd/man/hwdb.html'."\n";
+	print $outUPower '# (or equivalent for the version of systemd used in your distribution)'."\n";
+	print $outUPower '# Note that "During runtime, only the binary database is used" as compiled'."\n";
+	print $outUPower '# from files like this by e.g. `systemctl restart systemd-hwdb-update.service`'."\n";
+	print $outUPower '# (if you edit your copy locally or maintain a site-local override file in /etc).'."\n";
 
 	# Device scanner header
 	my $outDevScanner = do {local *OUT_DEV_SCANNER};