I haven't even heard of this one. The foreign press has nothing on a "China Only" Curriculum in a news search. This makes me suspect it's likely either a rumor or an incorrect name for a proposal than a policy or even an announcement of an upcoming policy.
Generally, there are three phases to any major policy.
1. A general concept is announced.
2. People wildly speculate about all possible ways to interpret it. Outside press often sensationalizes the worst possible misinterpretations.
3. The detailed rules come out a few days or weeks later and we all find out what's really happening.
Yes, there are occasionally surprises where the announcement comes with full rules attached, but those aren't as common.
Additionally, big policy changes usually get tested somewhere. The economic opening up of China was tested in special economic zones. Common Prosperity is currently being heavily tested in one province. This allows concepts to be checked for viability and viable concepts to be further optimized before being rolled out nationwide. Again, there are the occasional nationwide surprises, but those are not so common.
Check and see if you can find an online source for this. That should make it easier to see if this has a different name and whether it's a rumor, a proposal, or something else.