Лицензия GPLv2 or later - Юридические вопросы

No, it is not GPL, it is GPLv2.0 and you should follow the copyrights of the GPLv2.0 versions, above all:

GPL 2.0 license 1, 2 c)

1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.

You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

2 c) If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display an
announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
these conditions, and telling the user how to view a copy of this
License. (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)

Если модифицированная программа обычно читает команды в интерактивном режиме работы, вы должны сделать так, чтобы при запуске для работы в таком интерактивном режиме обычным для нее способом она печатала или выводила на экран объявление, содержащее соответствующее уведомление об авторских правах...