On Jun 30, 2018, at 20:04, Eli Zaretskii <eliz@gnu.org> wrote:

From: Jean-Christophe Helary <brandelune@gmail.com>
Date: Sat, 30 Jun 2018 17:57:32 +0900

If I find a program in C (gpl3) and I adapt it to Emacs Lisp what is the situation regarding authorship/copyright/licence ?

Please elaborate on what you mean by "adapt it to Emacs Lisp".