Joe Belfiore, Microsoft's Vice President of Windows and Windows Phone user experience, confirmed the existence of File Manager app when the question was asked during a Reddit Ask Me Anything (AMA) session on Friday.
" *** YES *** We are doing a File Manager for WP8.1! I know a LOT of you are looking for this (thanks for the tweets, I've read them all). In fact, I've been running a build of it on two of my phones for the last week or so and it's getting to pretty good shape," Belfiore answered enthusiastically.
He had also shared a link that contains six screenshots of the unreleased app, and further added that Microsoft is expecting to "get it into the store HOPEFULLY by the end of May."
The teased screenshots indicate that with the File Manager app for Windows Phone 8.1, users will get the ability to navigate through the device's built-in storage as well as external. The app will also enable user create new folders, move files from one folder to another, and search ability with in folder.