When creating your own Content Security policies for uploads it would be really helpful to be able to create a notification that would be displayed to an uploading user. The notification would be able to be configured by an admin user to explain the reason for why a file upload was prevented.

Without these types of notifications we have users who may upload files and then needless work exists to find out which user uploaded a file type we do not accept to then notify the end user that the file type is not acceptable and then have the user upload a file again. If we could just get the user to know which file types were allowed at upload and the reason if the upload was blocked that would be very helpful.