How to enable/access radio streams in ETS2 on Debian (installed via Steam)?

I can't seem to access internet radio streams in ETS2. I don't seem to have the button?! I've seen in a Youtube video, that there is a "Radio stream" tab (to the right of "Music player") But I don't have it, see my screenshot:

FWIW, I have the file where the streaming URLs should go (Euro Truck Simulator 2/live_streams.sii).

Does anybody know whether there's an option somewhere to enable it somehow? Or has it been removed in newer versions? Or is it missing from the Linux version for some reason?

It seems this feature is missing from ETS2 on Linux! :(

https://forum.scssoft.com/viewtopic.php?f=119&t=212257

No word from the devs on if/when it might be added.