That is where you consult the schematic, or ideally the Bill of Materials, in the VF2L documentation and see what was planned. On page 15 of the schematic the part that was NC (not to be connected) to the eMMc pad U25A was originally meant to a 32 GB eMMc without any part number listed 
Usually part numbers are given, was worth a look anyhow.
With the part number I hopefully could have found out more information about endurance.
EDIT: I looked at scaled up images of eMMc in photos of the VF2L board from the documentation I can not make out the part number but it appears to be a “rayson eMMc”. The logo matches exactly. I’m going to assume that it is a 64GB consumer grade eMMc (TLC part number R570B64G4516G or R570B64G4M08G) instead of an industrial/automotive grade (TLC part number AT70B64G3Y05G).
Either way TLC not bad (original TLC NAND was typically 1,000 erase/program cycles per 4KB block ; modern 3D TLC NAND is typically 1,500–5,000 erase/program cycles per 4KB block), considering that there are about 16 million 4KB blocks in the 64GB eMMc, a good wear leveling algorithm would make these last long enough under typical usage.
EDIT2: Just thinking about it a bit more, there is always the possibility that StarFive went with a different eMMc part number from a different vendor for the final design of the VF2L boards. That the part used in the photos is not the part that ships/will ship/has shipped 