Overview:
---------
After having update to openSUSE Leap 15.1, I am no longer able to get the
LibreOffice offline help.
Before the upgrade (from openSUSE 15.0), the offline help worked as expected.

The only other similar Bugzilla entry, I have been able to find was:

  #1096360 No LibreOffice offline-help & language packs in repository

but this does not apply here, because the files in question in that Bugzilla
are all in place now, as far as I can figure out.

Steps to Reproduce:
-------------------
Upgraded from openSUSE 15.0 to openSUSE 15.1 using an USB stick.

When clicking on "Help -> LibreOffice Help" or hitting F1, all I get is the
"Firefox - Choose User Profile" selection window, instead of the help window
from LibreOffice!

Actual Results:
---------------
A pop-up window from Firefox requesting me to select one of my profiles.

Expected Results:
-----------------
A pop-up from LibreOffice with the offline help menu.

Build Date & Hardware:
----------------------
Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz (64-bit)

$ cat /etc/SUSE-brand 
openSUSE
VERSION = 15.1

$ cat /etc/os-release
NAME="openSUSE Leap"
VERSION="15.1"
ID="opensuse-leap"
ID_LIKE="suse opensuse"
VERSION_ID="15.1"
PRETTY_NAME="openSUSE Leap 15.1"
ANSI_COLOR="0;32"
CPE_NAME="cpe:/o:opensuse:leap:15.1"
BUG_REPORT_URL="https://bugs.opensuse.org"
HOME_URL="https://www.opensuse.org/"

These are my installed LibreOffice packages:

$ rpm -qa '*ibre*' | sort
libdjvulibre21-3.5.27-lp151.3.3.1.x86_64
libre2-0-20190901-lp151.81.2.x86_64
libreadline6-6.3-lp151.2.3.x86_64
libreadline7-7.0-lp151.10.3.1.x86_64
libreiserfscore0-3.6.27-lp151.2.3.x86_64
libreoffice-6.2.8.2-lp151.3.2.x86_64
libreoffice-base-6.2.8.2-lp151.3.2.x86_64
libreoffice-base-drivers-firebird-6.2.8.2-lp151.3.2.x86_64
libreoffice-branding-upstream-6.2.8.2-lp151.3.2.noarch
libreoffice-calc-6.2.8.2-lp151.3.2.x86_64
libreoffice-calc-extensions-6.2.8.2-lp151.3.2.x86_64
libreoffice-draw-6.2.8.2-lp151.3.2.x86_64
libreoffice-filters-optional-6.2.8.2-lp151.3.2.x86_64
libreoffice-gnome-6.2.8.2-lp151.3.2.x86_64
libreoffice-gtk3-6.2.8.2-lp151.3.2.x86_64
libreoffice-icon-themes-6.2.8.2-lp151.3.2.noarch
libreoffice-impress-6.2.8.2-lp151.3.2.x86_64
libreoffice-l10n-en-6.2.8.2-lp151.3.2.noarch
libreoffice-mailmerge-6.2.8.2-lp151.3.2.x86_64
libreoffice-math-6.2.8.2-lp151.3.2.x86_64
libreoffice-pyuno-6.2.8.2-lp151.3.2.x86_64
libreoffice-qt5-6.2.8.2-lp151.3.2.x86_64
libreoffice-share-linker-1-lp151.3.3.1.noarch
libreoffice-writer-6.2.8.2-lp151.3.2.x86_64
libreoffice-writer-extensions-6.2.8.2-lp151.3.2.x86_64
libreofficekit-6.2.8.2-lp151.3.2.x86_64
librepository-1.1.3-lp151.3.44.noarch
librest-0_7-0-0.8.1-lp151.49.1.x86_64
librevenge-0_0-0-0.0.4-lp151.33.1.x86_64
librevenge-stream-0_0-0-0.0.4-lp151.33.1.x86_64
$

What to do:
-----------
How to fix this, so that the LibreOffice offline help becomes available again?