heic thumbnails

Hi,
I have a question about thumbnails of heic images.
In Leap 15.4 in order to have heic support in plasma
you need to install libheif from packman and
following what is written here: https://bugs.kde.org/show_bug.cgi?id=444976
and here: https://invent.kde.org/network/kio-extras/-/commit/667f8dd3ee884192602a92429f5fe10f9259303d
it is necessary to put in /usr/share/kservices5/imagethumbnail.desktop
  MimeType=image/*;video/x-mng;
With that in place dolphin is able to show thumbnail preview of heic images.

Now I'm testing Leap 15.5.
thumbnail preview of heic images still does not work
and the file /usr/share/kservices5/imagethumbnail.desktop does not exist anymore.

Any suggestion about how to make dolphin show thumbnails of heic images
in Leap 15.5 (and tumbleweed as well)?

Regards,
Giacomo