Yeah, the audio distribution component is part of the Oppo. It’s the subsystem that splits the stream for all of the different outputs and possibly does some output specific processing.
This topology was judged too complex/variable/situation-dependent to make explicit in signal path–however, their quality indicator (lossless or enhanced) should accurately reflect whether processing is happening in the path to the high quality analog outs on the back.
This will vary based on how you have the device configured. Stuff like bass management, speaker size, delay/distance, etc might introduce processing to the chain.