Comment by darkwater

No, A: and B: were for floppies, when having 2 floppy readers was the norm.

But anyway ignoring the sarcasm my question was implying: if this is totally customizable in Windows, why Microsoft still ships C: (or whatever other letter) as the default name for the first user partition? Show it to legacy programs with hardcoded values to maintain compatibility, but at least in Explorer and MS controlled software, use some more modern/legible name.