No new feature, yet contains breaking changes.
Allowing code to be properly ready and tuned for the next major release. Where the new features will be actually introduced, hopefully, without new bugs.
By all means make breaking changes, just maybe tone down the marketing.
In my opinion this goes WAY beyond the usual changelog entry in other repositories.
I think it's important to understand though that React is _marketed_, and unfortunately for many a name as clearly stated as this will likely define their expectations significantly. This could be especially pronounced for those who are less proficient in English.