Information about the .plt (plt) file type

Below is all the information we have available on file about the .plt (plt) file type.

.plt
Plot file. Typically a plot file in HPGL.

Where this is available we would like to include file format information on .plt files, as well as information on how to view or open files of type .plt. If you know of any information which we have missed then please let us know.