Re: Licensing of licenses

Alex wrote:
> Have others had the same questions before and come to good answers? Or are these the wrong questions to ask in the first place?

You're not alone; as a contributor and Debian Maintainer I've asked this question too and it's a very good one. To give a better example of the phenomenon we're talking about, the first sentence of the GNU GPL 3.0 says
> Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
I share your concern that making a claim in debian/copyright that such a license text *itself* is libre is technically wrong, and a lie at worst.

I don't recall if I ever uploaded such a package to the Debian archive or if this were just a draft, but when deciding on the debian/copyright text for some package I did something along the lines of

Files: COPYING
Copyright: 2007 Free Software Foundation, Inc.
License: FSF-verbatim (this is a name I made up)
 Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

This isn't something I'd recommend others do widely; in hindsight it's kind of silly, but I was drove to it after seeing the Lintian warning and was feeling creative.

Here are some similar issues we might get inspiration from:
 • In general, when software requires retaining authorship information or copyright statements (as most software does), this is still considered libre, even though it is a prima facie limitation on your ability to redistribute such a modified version. This policy, which I like to call "integrity of authorship", is supreme. Even if by unspoken agreement, it is axiomatic that authors have the right to make their authorship information forever† inseparable from the work. This might be needed to enforce license terms.
 	‣ Please note, however, that the author can't require a passage to be "cemented" into a libre work in general: see Debian's General Resolution about the GNU Free Documentation License for an example. There it was decided that "invariant sections"—sections that cannot be removed from the document, but which contain text other than fundamental integrity of authorship info—do infringe the freedom to modify and redistribute. Despite common misunderstanding, GFDL-licensed works are allowed in Debian without additional reservations as long as they don't have such invariant sections. 
 • I can't find a reference to the thread at the moment, but on some Debian mailing list a predicament was pointed out with public keys like OpenPGP keys: you could say that the private key is the preferred form for modification. In that thread, the conclusion was similar: a key identifies an author, and as an identifier and something used to assert integrity of a work (such as a digitally signed one), it would be plainly absurd to expect the "preferred form for modification" to be available. If it were to be, the keypair would cease to be a keypair at all.

From this, I we may infer that specific limitations on modification are acceptable for the Debian archive, and incorporated into the definition of "free software" at least informally, when those limitations are minimal but absolutely necessary to procure a free work. To put it frankly, licenses such as the GNU GPL are non-free by the textualist interpretation of the definition of a free work. However, its purpose in being the effective license for the work it is coupled with makes it, in the circumstances, admissable "as if" it were libre by the purposivist point of view.
The DEP-5 copyright file is intended to serve the same function as the copyright and licensing statements in each of a package's files, and in practice it's usually an aggregation of excerpts from the source files. Just the same, it is up to the reader to decide if a license is amenable to them, and as a downstream redistributor would *not* be Debian, by definition, it is best to omit constructions that could mislead them (such as saying the GNU GPL text is "free", because it's technically not, even though the DFSG Team may as well think of it that way). It is important to keep debian/copyright accurate then, and not embellish details about the "license of a license".

It is more safe to say nothing about the license of a license than to make up something misleading. So how do we want to handle this?

 • Remember that DEP-5 is mainly a proposal, a suggestion, and some situations are so complex they can't be reflected in DEP-5 at all. For example, there are situations where a binary package must have the Built-Using header to indicate that its source is not completely drawn from its own source package, but perhaps from other source packages. Usually, the built binary package is also responsible for retaining license info *from those other binary packages from which it incorporated portions of at build-time*, in which case some creativity is needed... This is hard to describe succinctly, so if you want examples, look for source packages that Build-Depends on binutils-source, say.
	As DEP-5 doesn't handle the "license of licenses" situation in a practical and scalable way, it is sensible to omit "license of license" information altogether.
 • Lintian is also just a suggestion. Lintian overrides should ideally not be used to paper over Lintian bugs or misjudgments that can be fixed in Lintian itself. Lintian could recognize when a file is a license text and forgive that file being omitted from debian/copyright, or as an alternative to heuristics a manual override could be justified. DEP-5 could also introduce a magic null-like license name or convention for the problem.

Anywho, in conclusion, this mail of mine is an argument to do anything *except* use a construct that suggests the license text itself is free, such as a broad "Files: *; License: GPL-3.0". That is incorrect and would imply the user has certain freedoms which they do not—which is the very worst case scenario for anything involving curation of copyright and license info. Ben pointed out the bug against Debian Policy to discuss a solution, and perhaps the Lintian folks could tailor their checking some, but otherwise use your best judgment. For your tool, simply omitting the LICENSES/ directory from debian/copyright and letting Lintian complain about its omission (in the absence of precedent that silencing it would be okay), is justified, I think, and perhaps your best choice.
Thanks for your care in working on Debian.

 † For this entire discussion, we presume that the author's copyright is still sound and not expired or retroactively waived.

-----BEGIN PGP SIGNATURE-----

iPsEABYKAKMWIQSiPzylvTnZ6xisfzWz9N0oYfTNugUCagjRR3IYaHR0cHM6Ly9q
b2huc2NvdHQubWUvLndlbGwta25vd24vbmkvc2hhLTI1Ni9zWUF3OTN6QUVrRkIy
RDREM1hOemRSeHEyMFBjNnByZGdtbEVWeXo0QUZRP2N0PWFwcGxpY2F0aW9uJTJG
cGdwLWtleXMSHGpzY290dEBwb3N0ZW8ubmV0AAoJELP03Shh9M26oH4A/RF1qx+C
EPJs8HUZAiG2mAlN7jpZioFlhFOisoetI6WOAPwLq9HP9+C4H6W1fMYe9gZyEu2z
6NdVrlqns20hDKcJAQ==
=HH/5
-----END PGP SIGNATURE-----