See this mailing list thread:
My understanding is that this clause doesn’t apply to the new version of the CC license we selected, and we should have removed it when we changed license. Since this is an administrative detail rather than an actual change in the default license, I propose we just fix the page without disrupting people with an announce-list post. Anyone have any concerns with that?
In my perspective, this is a clerical error from the previously-announced and voted-upon change to the CC BY-SA 4.0 default content license. I see the previous announcements and PR we did for this change as sufficient, so I believe it is fine to go ahead and make the change.
An aside, but the Legal thread is quite interesting. I agree with @ngompa’s general sentiment about the value of the explicit agreement and the role of the FPCA in the project. Instead of opting to strike it out altogether, I think we could instead work on being better about talking about it, and how it is actually one of the many subtle, creative ways that Fedora empowers its contributors.
But I know this thread is more about logistics on the wording change, so maybe I should go weigh in on the Legal thread instead 
Sounds reasonable to me.