I recently uploaded a new version of my app to itunes connect. My app got rejected with this note
Your app uses the \"prefs:root=\" non-public URL s
At the end the one with the issues was AmazonFling that was not listed on the pods because was installed using another method. See the forums post about it: https://forums.developer.amazon.com/questions/167282/apple-app-rejected-because-of-non-public-apis-refe.html
AmazonFling does not have update yet (as of Apr 27, 2018) so I removed it until they update it.
Fixed in AmazonFling 1.3.2, released on the same day. See https://developer.amazon.com/fr/docs/fling/release-notes.html