This app displays the type of a file. It’s helpful when you have to find out the type of file you’ve never seen before or the file does not have a file extension.

If the file cannot be read, or its file type is undetermined, This app tells you what kind of file it really is. 
This app only works locally without going through the server. It allows you to detect file-type instantly, real-time. You don't need to upload files to any server. It's very safe, and guarantees privacy. 
You can select any files to detect from your local computer and from Google Drive directly.
No file-size limit. You can open a large file to detect the file type.