I’ve made the same test with another UPnP Server software - Asset. Results similar to Jriver.
If I choose settings for output DSF/DFF files “as is” that I can play them on PWD with indication of 88kHz on PWD screen. Screenshot is here.
Description from Asset manual:
“DSD handling: ‘as is’ sends untouched audio/x-dff or audio/x-dsf. ‘as Wav’ decodes the DSD to PCM. ‘as DoP’ embeds the DSD bitstream into a WAVE file, requires a DoP compatible DAC, only DSD64 files are supported”
So, the question is still actual. It really seems that PWD with Bridge II play native DSD.