News:Relicensing to MPL2!
We are in the process of relicensing to the MPL2 license.
See the official MPL2 FAQ.
Like the LGPL, the MPL2 is a weak-copyleft license. It is however a bit more liberal, as the copyleft does not propagate across source files. It's a concept known as "file-level copyleft".
The MPL2 is GPL-compatible and LGPL-compatible.
The MPL2 is 3x shorter than the LGPL+GPL (note that the LGPL is an addendum to the GPL) and is much, much easier to read and understand.
This process has been worked on for the past 6 months on the Eigen mailing list and we are now only waiting for agreement from all contributors, and trying to figure what to do with third-party code.
If you are interested in details, please see the mailing list archives. If you contributed code to Eigen, please respond to the mailing list thread collecting contributor agreements.