I don't think contributing back on Blue Oak terms is a condition of the Blue Oak Model License, in the sense of https://www.apache.org/licenses/LICENSE-2.0#cont

I don't think contributing back on Blue Oak terms is a condition of the Blue Oak Model License, in the sense of https://www.apache.org/licenses/LICENSE-2.0#contributions https://www.apache.org/licenses/LICENSE-2.0#contributions. Rather, the Blue Oak Model clearly expresses the expectation that all contributors will do so. Expressing that expectation in writing can help make a legal case that submitting a contribution for inclusion in the public project implies a license under the same terms. But that's a distant second best to creating a written, public record of each contributor's affirmative intent to license their work under Blue Oak Terms. That evidence doesn't have to look like a "formal" CLA. It could be as simple as a public comment on the PR: > I license my contributions under Blue Oak Model 1.0.0. It could be as simple as having contributors add their names to a THANKS or AUTHORS or CREDITS file in the repo, under a note that everyone licenses BlueOak-1.0.0, with Git commit data showing each contributor added their own name.