GPL compatible alternative to LPPL?

Question

Problem

Sometimes, I write latex templates (e.g. to account for department-specific guidelines for theses etc.), and wonder how to license them.

Background

The IEEEtran latex class is licensed under the LaTeX Project Public License (LPPL) v1.3. According to the Free Software Foundation (FSF), this is a free license (which is good), but not compatible with the GNU Public License (GPL) (which may be bad, depending on circumstances). There are also templates for specific IEEE conferences or journals, which to my understanding are licensed in the same way.

What I found

Templates

There seems to be some debate about what a latex template is (as distinction from classes or packages). However in this case, I think it is quite straightforward: There is the class (IEEEtran.cls) and there are some templates (e.g. bare_conf.tex), that follow the appropriate layout guidelines. This is what I mean by "template".

Creative Commons

If I want to copyleft the content of my work, I can use a Creative Commons (CC) license, which is compatible with the GPL. However, I don't know if a template counts as content (my guess is that it doesn't).

LPPL restrictions

According to this answer, I'm free to license my tex files in any way I like, as opposed to being restricted to the LPPL. So I could just use the GPL, but the FSF recommends to "license your templates under simple permissive terms" (seen here).

Multi-licensing

I could use two licences (e.g. GNU and LPPL), so the user could decide which one to further use. But this just leaves the user with my original problem.

Question

Is there a GPL compatible license suitable for latex templates, that can be used instead of LPPL?

Edit

I have a strong preference for copyleft licenses. The reason why I asked about an alternative to LPPL, which is not copyleft, is that it seems to be a standard license for latex projects.

Answer 1

Generally, a template, in the context how you appear to use it, is a bare-bones document that people can copy and flesh out with their own content. The template document gives some indications how the author of the template thinks such a document should be structured.

As using such a template always starts with making a copy of it and then making changes to that copy (usually by adding stuff), copyright law states that the final document is a derivative work of the template. Copyright law also states that a derivative work may only be created and distributed with permission from the author of the original work (the template). This is where copyright licenses come into play, because they are the way in which such permission is granted and they specify the conditions under which the permission is granted.

Maybe you can already see the problem with using a copyleft (or share-alike) license for a template: all documents written using that template must use the same license as was used for the template itself. Many people don't realize that and I am not sure if your department would agree that all theses must be published under a copyleft open-source license. That is why the FSF recommends to use a permissive license for templates.

As for which license you can use for your own latex templates, don't focus too much on GPL compatibility. While using a GPL compatible license for software is a good thing, as nearly all software sooner or later comes into contact with the GPL license, LaTeX forms essentially an ecosystem of its own where GPL compatibility is not an issue.

You can use the GPL or CC BY-SA licenses for your template (yes, your template counts as content), but then you run into the issue outlined above that any document written using your template must be published under the same license.

As a template should not put too much burden on the people that use it to write a document, I recommend to use a simple permissive license, like 0BSD or perhaps MIT for templates. Both of those are compatible with the GPL and place very few requirements on the users of the template.

For LaTeX class files and packages that accompany the template, I recommend that you use the LPPL license. That license is specifically tailored for packages and classes in the LaTeX ecosystem.