Hi,
The reason behind the incompatibility of libwidevinecdm.so could be that I'm using the Firefox distributed directly by Mozilla, and not the one provided by Debian.
> Can you verify that Widevine is working correctly for you in Firefox?
Netflix works, so I assume Widevine works.
> Do you happen to have a second system you can test?
I don't have another Debian system around.
Kind regards.