davcefai, that claim comes from Jerry Pournelle, who claims that he personally saw Kildall type the command and wrote it down. He has been asked several times to produce the command and has not done so.
The Evans book mentions Kildall using such secret command to catch other companies copying CP/M, but not Microsoft. Kildall wrote a unpublished memoir shortly before he died that was very bitter about the whole affair, and if he had such damning evidence he certainly would have produced it. There is no indication that he did.
There is no "vindication" of Kildall here nor any finding that revises the history of CP/M and DOS in the least, just a finding that Paterson filed a sloppy, emotional lawsuit, which would be obvious to anyone reading it.
If you want to know the full story, it's all explained in detail, with sources, in Wikipedia's articles on Kildall and 86-DOS.