Bluray backup directories

[hhmit164]

I made a backup of a bluray disc and ended up with 4 directories: BDMV, CERTIFICATE, KDM, MAKEMKV.

My plan was to backup my optical disk to hard disk in case the original gets scratched, etc. Do I need to keep anything other than the BDMV directory?

In particular, the KDM directory contains a bunch of *.bin files that total a whopping 56.2 GiB, more than the 2-layer disc should be able to hold. The BDMV directory (a reasonable 33.5 GiB) seems to be all I need to create mkv files from one of the playlists, so I am curious what the other 3 directories are for, especially this KDM directory.

[dcoke22]

I make blu-ray backups all the time. I don't think I've ever had a KDM folder in a backup.