Look for the "Apple Developer Program License Agreement" at https://developer.apple.com/terms/
However, said agreement doesn't saying anything other than:
3.1 Apple may at any time, with or without prior notice to You (a) modify the Apple Maps Service and/or the MapKit API or MapKit JS, including changing or removing any feature or functionality, or (b) modify, deprecate, reissue or republish the MapKit API or MapKit JS. You understand that any such modifications may require You to change or update Your Applications, website, or web applications at Your own cost. Apple has no express or implied obligation to provide, or continue to provide, the Apple Maps Service and may suspend or discontinue all or any portion of the Apple Maps Service at any time. Apple shall not be liable for any losses, damages or costs of any kind incurred by You or any other party arising out of or related to any such service suspension or discontinuation or any such modification of the Apple Maps Service, MapKit API, or MapKit JS.
Make of that what you will.
>current day licensing requirement
Doesn't look like anything has changed since '18 - see https://developer.apple.com/maps/web/
"MapKit JS beta provides a free daily limit of 250,000 map views and 25,000 service calls per Apple Developer Program membership. For additional capacity needs, contact us"