I know a Mac volume can be renamed... obviously.
But if you look at the output of
diskutil you will see that a volume also has a "device name" that corresponds to the name it was given when it was formatted:
diskutil info /dev/disk0s1 | grep 'Media Name'
Running it on your root volume you will probably get "Macintosh HD" (or else something like "Untitled 1" if that's how you left it when formatting in Disk Utility). It seems this doesn't change when you rename the volume after the fact.
Why do these different names for the same volume exist?
Does anything even refer to this hidden name?
Can it be changed?