Does iOS AppStore prohibit Youtube Downloading apps? I am currently developing an app that allows users to search for a youtube video and then allows them to download the video offline for viewing when there is no wifi/cellular coverage..

I noticed that the AppStore lacks this category of apps, or to put it in other words: apps like these appear for a short while before being removed, or updated to stop downloading videos.

So, there must be some guidelines on what apps are allowed to exist in the appstore and clearly youtbue downloaders are not. Where can I read those guidelines?
Here's the official Apple guide 


  5.2.3 Audio/Video Downloading: Apps should not facilitate illegal file sharing or include the ability to save, convert, or download media from third party sources (e.g. Apple Music, YouTube, SoundCloud, Vimeo, etc.) without explicit authorization from those sources. Streaming of audio/video content may also violate Terms of Use, so be sure to check before your app accesses those services. Documentation must be provided upon request.