www.makemkv.com

I have two files:
and
Is there any difference between the two, besides the HDR format line noting it's HDR10?

I'm assuming they're the same and the former is just missing metadata telling MediaInfo it is HDR10?

For former is remuxed in 2017 and the latter is remuxed 2023, same UHD. Perhaps the former is remuxed with an nearlier version of MakeMKV, before it recognized HDR10 as HDR10 and able to put the metadata in the file or something?

I checked the changelog but couldn't find anything meaningful:

https://www.makemkv.com/download/history.html

Main 10 is the "part" version and L5.1 is the "level" version, nothing to do with HDR.

https://en.wikipedia.org/wiki/MPEG-4

https://makemkv.com/download/

It looks like MakeMKV 1.15.3 was when MakeMKV learned to extract HDR stuff out of a UHD. If your first file was created with an older version of MakeMKV, it is probably missing any HDR stuff that was on the disc.