Unofficial Licensing FAQ

== Is the Second Life Viewer GPL-compatible? ==
Yes and no. The viewer is licensed under the GPLv2 with an additional FLOSS exception. This FLOSS exception allows linking to GPL-incompatible libraries. If you remove the GPL-incompatible libraries and strike the FLOSS exception from the license, then the client is fully GPL compatible, and may then be distributed with other GPLed works linked with it.
Notable GPL-incompatible components:
* Fmod (audio library)
* Kakadu (JPEG2000 decoding library)
* Apache Portable Runtime (compatible with GPLv3)
Also see: FSF's wiki on GPL compatible licenses.
== Can Linden Lab incorporate contributions from us? ==
If you are not able to give permission to Linden Lab to re-license the contribution for use in their components and distribution, Linden Lab will not be able to incorporate such contribution. Linden Lab has created a means for you to grant such permission to them by their contribution agreement, which allows Linden Lab to copyright the contribution and ensures that no patent can be enforced against the contribution by the submitter.
== Can the contribution be under the GPL? ==
If the contribution does not make a single or combined work with the viewer, it may be accepted in an aggregated form no matter who the copyright holder is at the time.
If the contribution uses the standard GPL and you are not the copyright holder of the contribution, Linden Lab will not be able to re-license the contribution directly from you. Only the copyright holder is able to give such permission to re-license their code. Linden Lab cannot incorporate someone else's copyrighted work from you.
If you are the copyright holder and the contribution is under the standard GPL, you must allow Linden Lab to also copyright the contribution in order for them to re-license the contribution.
== Why does Linden Lab want to re-license the contribution? ==
* The Viewer Software is distributed under the GPL+FLOSS terms, which is not currently GPL-compatible
* The binary client distribution may contain unreleased source changes
* Linden Lab offers permissive commercial licensing terms to third parties
== What are the GPL+FLOSS terms? ==
The terms are based on the standard GPL but with an exception known as the FLOSS Exception. The FLOSS Exception allows Linden Lab to approve of licensed software and that may link, combine, or create a single work with the Viewer Software. Normally, the standard GPL does not allows other non-GPL works to link, combine, or create a single work that is under the GPL. In this sense, the exception creates the incompatibility with the GPL. Note, the base work of the Viewer Software may be derived or modified to remove GPL-incompatible works and then the FLOSS exception may be removed, which would render a standard GPL'd version of the Viewer Software.
== What is FLOSS? ==
Free/Libre/Open-Source Software (FLOSS) denotes software that can be freely run, studied, modified and distributed (for free or for a fee) once received. It doesn't necessarily mean it is available free of charge or freely available at all.
In practice however, most Free/Open-Source Software tends to also be available free of charge.
== Should I contribute under an approved license listed in the FLOSS Exception instead of the GPL? ==
Using something like the BSD/MIT license would help solve the issues with the GPL-compatibility, and the ability to relicense, but it does not solve some of the patent issues within the contribution normally covered by the standard GPL. Linden Lab offers the Contribution Agreement, instead. Also note that some of the licenses listed in the FLOSS exception are GPL-incompatible.
== Should I sign the Contribution Agreement? ==
Consider a comparison. With license agreements other businesses have offered about contributions, you may find they tend to lean towards non-disclosure terms or that you have to give up ownership of your contribution. In comparison, the Linden Lab's Contribution Agreement is an excellent offer that allows you to continue to own your contribution. However, you may wish to communicate directly with Linden Lab to perfect an agreement if you do not find the default terms of the Contribution Agreement acceptable.
== Is the artwork that comes with the client GPLed? == 
No, it is released under Creative Commons Attribution-Share Alike 3.0 license. Be careful to heed the trademark policy if you plan on distributing this artwork.
== What about the in-client LSL documentation? ==
Linden Lab has not made an official policy announcement in regard to this. Informally, however, they have said that they will allow it to be posted to this wiki, so one might assume it is under Creative Commons Attribution-Share Alike 2.5 also.
== Is the new Voice feature proprietary? ==
Yes, at least in part. Linden Lab seems to be trying to keep it in a separate process so that the viewer code will not need to be linked directly to any proprietary dependency, avoiding further GPL incompatibility. The codec it uses is covered by patents, so it is doubtful it will ever be fully distributable. This is tentative information as of March 2007, and may change as this feature develops.
: Voice is now provided by the technology developed by Vivox, a company acquired by Unity. — Gwyneth Llewelyn (talk) 13:20, 31 August 2022 (PDT)
== Does the contribution agreement make me give up all rights under any patents I might hold? ==
No. The agreement only requires you to grant a license on patents that cover your contribution, for that contribution. However one should carefully consider the ramifications. Because Linden Lab offers permissive licensing to third parties, they are also licensing your patents that cover your contribution to those third parties. This could affect the enforceability of your patents against those third parties. A consultation with a patent lawyer would be in order if you think this might affect you.
== Which Libraries that the client uses are GPL-incompatible? ==
Please see Third_Party_Libraries.