DPL is for time being used to connect the slave speaker to the master speaker (BL50/90).
Official definition is: 'Includes proprietary B&O data channels for inter-loudspeaker communication'.
It is based on the AVB (AudioVideoBridge/Bridging) technology.
Since there is a DPL-input port on the master speaker and the BS Core has a DPL-output port* it (IMO) is likely that it will be used for the communication
between source systems and the speaker/s in the future - as a successor for the old analog PL.
Note! There are no official statements or informations on this yet!
The WPL is basicly the same - using WiSA as the protocol for the wireless connection
*This output is declared 'for future use' in the specs of the BS Core.
Hope this helps answering your question.
MM