Manifold's Github page says at the bottom of its readme:

By contributing to this codebase, you are agreeing to the terms of the Manifold CLA.

With the CLA saying that contributors give away certain rights to Manifold.

But no explicit agreement is required, and it'd be pretty easy for someone to submit a pull request without having read the entire readme.

If the contribution structure is significantly changed, the new one doesn't count. If a court case is settled, if it's obvious how it would have resolved I'll resolve the market based on that, otherwise it doesn't count.