mojave - data ???
My Macbook Pro has developed a drive called MOJAVE - Data
I don't know where it has come from or if I can delete it. It seems to be empty but uses up storage ??
Question marked as
Catalina splits the drive in two, normally Macintosh HD & Macintosh HD-Data, I guess your Drive was named Mojave instead.
I'd make a good backup or clone or two, reformat the Drive& Restore or clone back.