Friend i dont know what's going on exactly, i also expected to receive the warning email soon after upload, but i didnt get any warnings for my app.
I do have a friend who got the email though, i think he got it soon after the upload to testflight and it looks something like this:
We noticed one or more issues with a recent submission for TestFlight review for the following app:
• [redacted]
• Version 1.3.2
• Build 81
Although submission for TestFlight review was successful, you may want to correct the following issues in your next submission for TestFlight review. Once you've corrected the issues, upload a new binary to App Store Connect.
ITMS-91053: Missing API declaration - Your app’s code in the “PlugIns/blaaaa.appex/blaaaa” file references one or more APIs that require reasons, including the following API categories: NSPrivacyAccessedAPICategoryUserDefaults. While no action is required at this time, starting May 1, 2024, when you upload a new app or app update, you must include a NSPrivacyAccessedAPITypes array in your app’s privacy manifest to provide approved reasons for these APIs used by your app’s code. For more details about this policy, including a list of required reason APIs and approved reasons for usage, visit: https://developer.apple.com/documentation/bundleresources/privacy_manifest_files/describing_use_of_required_reason_api