it must be E-ATX but it seems to not be identified/confirmed anywhere.
Not much is known about the asus KGPX-D24 it seems to have been sold in the RS500A-S6/PS4 1U server
it can now be found as a stand alone board on 2nd hand marketplaces
here is the spares documentation i could find on it and an attached images of the board in question
https://15h.org/images/7/74/RS500A-S6_PS4.pdf
Not much is known about the asus KGPX-D24 it seems to have been sold in the RS500A-S6/PS4 1U server
it can now be found as a stand alone board on 2nd hand marketplaces
here is the spares documentation i could find on it and an attached images of the board in question
https://15h.org/images/7/74/RS500A-S6_PS4.pdf
