Of course if you include the "function header" from some code in the training data (below) it will prompt GPT to generate the rest of the function. That's kind of exactly the point of it, it autocomplete on steroids.

  // CSparse/Source/cs_gaxpy: sparse matrix times dense vector
  // CSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved.
  // SPDX-License-Identifier:  LGPL-2.1+
  #include "cs.h"
  /* y = A*x+y */
  csi cs_gaxpy (const cs *A, const double *x, double *y)

It's like starting to sing "happy birthday to you" and being surprised that people in the room join in and finish the song.

Sure they make a valid point about including GPL code in the training data, but it's a little disingenuous to go to that extent to get Copilot to output the GPL code verbatim.

The sooner we have a test case go through the courts the better.