Hi,

I'd like to include Eigen's source tree into the repository of another OSS project publicized under LGPL2.1. In my understanding, this is allowed by the community of Eigen. However, I found that COPYING.MPL2 in Eigen's repository contains Exhibit B section at the bottom, which says

This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.

So it seems that Eigen's MPL2.0 license is not compatible with LGPL2.1. Is this correct? If so, is it safe to include Eigen's source tree into LGPL2.1 project, though?

Don't worry, it is safe to include it. This exhibit is not included in any of our source code files. Perhaps we could remove it from the licence file to avoid ambiguities.

Ah, I see. So Exhibit B is enabled only if the source code itself contains it, and this is not the case of Eigen. Thank you for the quick reply!