Selecting a convenient licence for distributing software or data may appears as a difficult task. This is because licences generally combines “permissions” (which are the main objectives and “raison d’être” of a licence) with other provisions that could be conditions or obligations and in some cases prohibitions.
The initial remark to be done is that a licence is necessary: indeed, without the permissions provided by the author or copyright holder, any use of the copyrighted material implies serious risks of copyright infringements.
Licence given by the author or copyright holder could be very permissive or general “just do what you want with this software or with those data”, which is close to a declaration of putting the work into “public domain”.
Even the most simple or permissive licences generally include the obligation to keep the existing copyright notices (The above copyright notice shall be included in all copies or substantial portions of the Software…) and (often in capital font) a liability exclusion clause: THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED…, etc.
What is – in principle - common to all “open source” or “free software” licences is the set of freedoms given to the user (or recipient, or licensee): the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or provide copies of the covered work.
However, other conditions or prohibitions may exist, as for example:
- The obligation to publish the source code in case a modified copy or a derivative is distributed, or to make it available in some human readable and re-workable form;
- The obligation to document any modification in the modified source code;
- The obligation to reuse the same licence (“share alike” or copyleft clauses) or a similar / compatible licence in case of re-distribution;
- The obligation to maintain the use of the work and the use of derivatives (even deeply modified or improved) “royalty free”;
- The coverage (or not) of “communication to the public”, i.e. via on-line services or the inclusion of the software into hardware devices;
- The acceptance or exclusion of patents;
- The prohibition to make a commercial use of the work.
As these provisions – and many other – may be combined in multiple licences (there are about 100 different models available) there is a great utility for licensing assistants or “wizards” application that will help authors (or licensors) to make their choice. In many cases also a work of software is provided under two or even more licences. This is called dual, or multiple, licensing. It is then to the recipient or licensee to select the most convenient licence, which will be important if this licensee decides to redistribute the work.
Some years ago, Joinup has provided its own “Licence Wizard” - https://joinup.ec.europa.eu/page/licence-wizard. This selection tool is passed on a hierarchical – multiple choice – process and has the merit to consider the European legal framework, which differs from the U.S. regarding liability exclusions, moral rights, linking for interoperability, and communication to the public.
The new « Licensing assistant » provided by the European Data Portal is especially well done as it facilitate the selection of wanted permissions (distribution, reproduction, creation of derivative works, sublicensing of copies or derivative, use or compatibility with patent claims), of resulting obligations (applying the same licence to derivatives – meaning “copyleft”, “lesser copyleft” or “share alike”, preserving copyright and attribution notices, state changes done in the copyrighted material) and of possible prohibitions (making commercial use of the data). See: https://www.europeandataportal.eu/fr/content/show-license . Of course, this Licensing assistant is focused on open data: no mention of the obligation to publish the source code for example, as this is typical for software.
The “Choose a licence” application developed by the major software forge GitHub is more convenient for software and provides a clear selection table where permissions, conditions and prohibitions are listed. This table is not presented as front-end (which proposes a too limited subset), but as appendix: https://choosealicense.com/appendix/
On his side, the Open source initiative (OSI) maintains its own list of “OSI approved licence” but the proposed categories https://opensource.org/licenses/category , which include “popular”, “international”, “special purpose”, “other”, “redundant” and “uncategorized” are of little interest for the candidate licensor and should be deeply reworked. The OSI site does not classify licences according to their provisions and – like GitHub and other U.S. initiatives, does not consider the specificities of the European legal framework.
The Free Software Foundation (FSF) is an important historical reference too, but its guidance is exclusively focused on its own “GNU” licences (the GPL, LGPL and AGPL). Therefore, open source licences are divided in two main groups: those which are compatible with the GNU/GPL and those which are not, where “compatible” means that the covered code can be used (copied or merged) for writing software that is distributed under a GNU licence. In addition, the FSF list informs on some “non-free” licenses, which is interesting, and provide rationale for explaining its classification. What is specific, the FSF site contains instructions aimed to canalise the behaviour of FSF followers: “Please do not release software under this license” or “We urge you not to use the XXX License for software you write”, etc. What is unfortunate is that delivered information is widely outdated, sometime based on errors or false understanding and therefore not reliable as it should be (especially concerning the EUPL that is still listed as non-compatible with the GPL, while it is compatible).
As a conclusion, making a perfect application for helping users to select the most convenient licence is not easy. It requests permanent updates and should combine experience from lawyers representing multiple legal frameworks. This task is still open!