How is the file system for recordings constructed? I know the partition table, but how are they linked together?

Does the FS_ROOT in this refer to the mem name of the partition table? In the recode example file, it’s user-defined, and I didn’t quite understand this part. I checked the RT-Thread documentation but couldn’t find it. If you could kindly provide a link for reference, or help me clarify this confusion, I’d really appreciate it. Thank you!

in the ptab.json file under board