Details on LLDP-MED TLVs?

Sadly no reply so far.

It likely is about what other vendors call Power over MDI which is a way for a powered device (PD) to tell the power sourcing equipment (PSE) over particular LLDP-MED TLV what power level it needs and the PSE can tell the PD the other way what it is capable of.

Likely ex-pse is what should be enabled on the switch side if you want PoE+ devices to properly negotiate power levels with the PoE+ switch. I doubt that ex-pd is likely only interesting to switches that can be powered over PoE themselves like the GSM5212P in the M4100 line where such a switch can ask for more PoE power when it needs to draw more when additional devices get attached to as it can do PoE passthrough up to a certain level while being powered over PoE(+).

I'd appreciate if someone from Netgear could comment on this to confirm or reject what I found based on guessing and comparing with other vendors who have a bit more documentation on that topic.