If you have the tracking bar turned on in the basic curves command, it will report the cursor X,Y,Z location as you move it around the graphics screen. You aren't missing anything; it wasn't super useful even 15 years ago.
- As Cowski notes, it ONLY applies to the "Basic curves" which Siemens is slowly phasing out,
but, after a quite long learning period / high threshold / trial and error it actually was useful.
