License groups

Welcome to the License Groups working page.

This is a small team in Gentoo that try to make heads & tails of license terms, so that we can detect conflicts between licenses in packages, and know when it's safe to redistribute distfiles, or include binaries in stages and media.

When is a license a free software license?
A free software license must grant the ”four freedoms“ to the program's users, as described in the free software definition:
 * The freedom to run the program, for any purpose (freedom 0).
 * The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
 * The freedom to redistribute copies so you can help your neighbor (freedom 2).
 * The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.

Some tests to check whether a license is a free software license have been created by Debian (taken from their DFSG FAQ):
 * The ”Desert Island“ test. Imagine a castaway on a desert island with a solar-powered computer. This would make it impossible to fulfill any requirement to make changes publicly available or to send patches to some particular place. This holds even if such requirements are only upon request, as the castaway might be able to receive messages but be unable to send them. To be free, software must be modifiable by this unfortunate castaway, who must also be able to legally share modifications with friends on the island.
 * The ”Dissident“ test. Consider a dissident in a totalitarian state who wishes to share a modified bit of software with fellow dissidents, but does not wish to reveal the identity of the modifier, or directly reveal the modifications themselves, or even possession of the program, to the government. Any requirement for sending source modifications to anyone other than the recipient of the modified binary – in fact any forced distribution at all, beyond giving source to those who receive a copy of the binary – would put the dissident in danger. For Debian to consider software free it must not require any such ”excess“ distribution.
 * The ”Tentacles of Evil“ test. Imagine that the author is hired by a large evil corporation and, now in their thrall, attempts to do the worst to the users of the program: to make their lives miserable, to make them stop using the program, to expose them to legal liability, to make the program non-free, to discover their secrets, etc. The same can happen to a corporation bought out by a larger corporation bent on destroying free software in order to maintain its monopoly and extend its evil empire. The license cannot allow even the author to take away the required freedoms!

Useful links

 * GLEP 23
 * FSF licenses
 * OSI licenses
 * GNU free software &amp; freedoms definition
 * Open Source Definition
 * Freedoc licenses
 * @BINARY-REDISTRIBUTABLE group