SubDFromMesh on Command line, doesn't show in the hint as you type

hello, just noticed that when typing the SubDFromMesh on the command line it doesn’t show up as you are typing in the command line auto hints that populate as your typing, Though the command did work (at least the way I was trying it with all the options to NO).
I am using 6.3 from 3/31/18.

That’s intended I think, it’s an “undocumented test command” hence no autocomplete…