Below are what the author understands of certain concepts of the EZSP API. They may be wrong - please correct.
ASH
"handles retries and ensures non-cryptographic packet integrity." [AN1125]
"The ASH framework handles the encapsulation of EZSP frames into a more robust UART protocol and occasionally does some of its own serial transactions for QoS purposes."
Pan id
( ) What is it?
Manufacturing token
EUI64 ID
EmberZNet PRO
The stack that runs within the Sonoff Zigbee 3.0 Plus V2 dongle. It's a full Zigbee stack that you can control via the serial (EZSP) interface.
It's all on the side of the NCP, so basically "you don't need to know". :)
NCP
Network Co-Processor. What the Sonoff dongle is to the PC it's connected with.