Here we go. Clarification from Apple itself:
As part of the App Store Improvements process, developers of apps
that have not been updated within the last three years and fail to
meet a minimal download threshold — meaning the app has not been
downloaded at all or extremely few times during a rolling 12 month
period — receive an email notifying them that their app has been
identified for possible removal from the App Store.
Apple always wants to help developers get and keep quality
software on the App Store. That’s why developers can appeal app
removals. And developers, including those who recently received a
notice, will now be given more time to update their apps if
needed — up to 90 days. Apps that are removed will continue to
function as normal for users who have already downloaded the app
on their device.
Good, clear clarification and response.