In order to support a custom paste behaviour, In my UITextView, which I set as its own UITextPasteDelegate in awakeFromNib(), I implemented textPasteConfigurationSupporting(_:,transform:).
When pressing the paste button above the software keyboard, in the callback of item.itemProvider.loadItem(forTypeIdentifier: UTType.rtf.identifier) I get an error
Error Domain=NSItemProviderErrorDomain Code=-1000 "Cannot load representation of type public.rtf" UserInfo={NSLocalizedDescription=Cannot load representation of type public.rtf, NSUnderlyingError=0x28374e8e0 {Error Domain=PBErrorDomain Code=13 "Operation not authorized." UserInfo={NSLocalizedDescription=Operation not authorized.}}}
even though the item.itemProvider.registeredTypeIdentifiers are
"iOS rich content paste pasteboard type", "Apple Web Archive pasteboard type", "com.apple.uikit.attributedstring", "com.apple.rtfd", "com.apple.flat-rtfd", "public.utf8-plain-text", "public.rtf", "public.html", "com.apple.WebKit.custom-pasteboard-data"
and item.itemProvider.canLoadObject(ofClass: NSAttributedString.self) returns true.
Even item.itemProvider.loadObject(ofClass: NSAttributedString.self) returns a similar error:
Error Domain=NSItemProviderErrorDomain Code=-1200 "Could not coerce an item to class NSAttributedString" UserInfo={NSLocalizedDescription=Could not coerce an item to class NSAttributedString, NSUnderlyingError=0x283497b70 {Error Domain=PBErrorDomain Code=13 "Operation not authorized." UserInfo={NSLocalizedDescription=Operation not authorized.}}}.