The DFSG vs the LPPL

I just saw this huge discussion over at the Debian-devel mailinglist about whether or not the LPPL (LaTeX Project Public License) is a free license. That is free in the Debian sense: it has be fulfill the DFSG (Debian Free Software Guidelines) before it can be included in the main section of the Debian archives. There’s currently lots of stuff in the archive that’s licensed under the LPPL, but the Debian guys would rather see that it was distributed under another license, or that the LPPL is changed to conform with the DFSG.

The problem seams to be, that the LPPL forbids you from modifying a file and then redistributing it using the same filename. This is important for us LaTeX folks, because one of the promises of LaTeX (and TeX) is, that a document processed today will look identical when it’s processed 10 years from now. If everybody is allowed to change important files, then that promise would be hard to keep. This isn’t just a theoretical concern — it has happened that someone changed the Computer Modern fonts made by Donald E. Knuth and distributed them as the original set. They thought that they were helping people by improving the fonts, but that wasn’t how others looked at it. I don’t know exactly what the problem was, but if they had changed the width of a character just a little, then it could mean that lines would be broken differently, something that must not happen. If an author has prepared a document using his own installation of LaTeX, then he has to be absolutely sure that the publishers version of LaTeX will place the letters at the exact same position on the page.

One the other hand, then the Debian guys want to reserver the right to change the files in their LaTeX distribution, in case they discover a security risk or something like that. This is a very hypothetical situation, but they want the right to do this anyway.

So, is boils down to a question of trust: do the LaTeX community trust the users not to cause havoc by distributing modified files from the core of TeX and LaTeX? Apparently not, and after the story about the improved CM fonts, I can understand their fear. I don’t think they fear that the teTeX maintainers would go crazy, it’s more about the principle that people has the option of changing those files.

I hope that they can works things out — it would be a real shame if this “battle of principles” should end with moving the teTeX packages to non-free, as almost everybody recognizes that TeX and LaTeX are some of the finest examples of free software.

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