The rules go into effect on October 3rd. Apple says that current software without a policy won’t be removed from the App Store, but they’ll need to link to one if they ship an update after that date.
In the wake of GDPR taking over policing privacy defaulters, becoming fully enforced on May 25th and Facebook suffered the consequences of its major Cambridge Analytica, data breach fiasco in March, data privacy has increased in prominence for tech companies. This new rule seems to be Apple trying to comply with greater expectations of transparency around how user data is handled and asking developers to regulate themselves.
Apple has already taken a strict unrepentant stance on apps it finds questionable, like Facebook’s data-sucking VPN app Onavo, which it kicked out of the App Store earlier this month