I just tried to go to Borrego (L08) to see if the box was there. The airport actually isn’t even there but the faded scenery of it is still identifiable, as are the box markers next to the runway.
I finally figured out how to add boxes to AFS2, but not AFS4 yet, but looking at the 2024 contest schedule I discovered that KLAA, KSEF, FATP and YWSG all have box marks clearly visible in satellite imagery.