FRA Airport has equipped ground vehicles with transponders

A couple of days ago, I noticed, that FRA Airport equipped all ground service vehicles with ADS-B transponders. When you have a look, you will see a large number of them over the whole airport area.

But unfortunately, they do have the wrong icon. On other airports (i.e. AMS), the icon of the ground vehicle is like a silver car, in FRA they use the icon for unknown aircraft type.

Any idea, how that can be changed? Do the admins read within this forum, or do they have to be notified on a different way?

Thanks for your help in advance!