The API guide you mentioned is the API guide for the PANS firmware. Sorry for the confusion, I agree the title of this document can be somewhat misleading.
The examples on Github use revision 2.04 of our deca_driver library. The documentation for this can be found in the “DW1000 Device Driver API Guide” contained in the The DW1000 Application Programming Interface software package, see DW1000_Software_API_Guide_rev2p4.pdf.
I would be possible to create a more advanced setup with multiple responders, but the example we provide on Github does not support this. PANS does provide a more advanced RTLS setup, but we can not release the full source code of this system. It is however possible to connect an external MCU / device to the DWM1001 and use the PANS firmware API over UART, SPI or BLE.
I hope this answers your questions