clim-utils again

Good day from Greg Bennett who is running sbcl-1.5.8 under linux mint 19.2 64-bit and mcclim code from  mcclim-20191008-get via quicklisp.

I would like to learn more about the coordinate system behind the &key arguments left top right bottom in the call to make-application-frame. This seems to be a coordinate system for a device which defaults to the full size of the root window, whatever that is.

As far as I can tell (some) details might be in the package clim-utils but this does not seem to be part of the mcclim I am using. Pointers to its definition and to the device coordinate system would be much appreciated.

Cheers /Greg