It could be an A/B test to see whether people without an existing subscription care about Claude Code (CC) at all. If they sign up then CC is disabled (or not as it is not really an issue to offer more). Capturing that info would definitely be useful to a growth team.

No, they're testing removing it from the Pro tier for new subscribers.

No I think the test is that some new sign ups won't get Claude code in that tier if they pick it and they're seeing if users will still pay for it without it?

A/B test to see how people react to changing the offerings

5000 angry users who leave? maybe keep it. 500000 users leave? pretend it was just documentation mis-prints or an oversight, etc.