Please add a `LICENSE` file to the repo

[mbrukman]

Disclaimer: I am not a lawyer and this is not legal advice.

---

First of all, thank you for sharing this project with us!

I noticed that the README.md shows this project is licensed under the GPL + a special linking exception:

ipe/README.md

Lines 39 to 61 in 56d9527

	### Copyright
	Ipe is copyright (c) 1993-2024 Otfried Cheong
	Ipe 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.
	As a special exception, you have permission to link Ipe with the CGAL
	library and distribute executables, as long as you follow the
	requirements of the Gnu General Public License in regard to all of the
	software in the executable aside from CGAL.
	Ipe 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. See the GNU General Public License
	for more details.
	You should have received a copy of the GNU General Public License
	along with Ipe; if not, you can find it at
	"http://www.gnu.org/copyleft/gpl.html", or write to the Free Software
	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

Please consider moving the license from README.md to a file named LICENSE in this repository. That way, GitHub will highlight this for repo visitors with a direct link to the license¹ and any third-party depending on your code can easily get the LICENSE as part of their transitive set of dependencies with clear terms, rather than having to hunt for it outside of the usual places.

Also, the text in the README.md currently is the short form referring to the GPL and not the full license; you can find the full text of the GPL at either of the following URLs (though you will need to add your custom exception there to have the effect you're looking for²):

• https://choosealicense.com/licenses/gpl-3.0/ (run by GitHub)
• https://www.gnu.org/licenses/gpl-3.0.txt

Note that if you were using the exact GPL (without the exception), it would clearly identify the project as being under the GPL, similar to the screenshot on this page (with license badge highlighted):

https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/adding-a-license-to-a-repository

Thank you!

Footnotes

1. It will be similar to this badge, except it will say "View license" instead since it would be a custom license, rather than the standard GPL-3.0. ↩

2. For reference, LLVM is under the Apache 2.0 with an exception; you can see the LLVM license for details. ↩