Thank you for your answer!
Definitely the former..
Here's what i'm thinking of putting in the code, along with a donate button (the 'software' is a php module for HumHub - an open source social network):
/**
* My Name
* Copyright (C) 2022
*
* Please consider making a donation using the button found on the main page of this module; it would help me greatly..
*
* This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
PS: note that this is only visible to administrators, so only they would see the donate button..