YubiKit
· This is a lightweight wrapper around the existing [Android APIs](https://developers.google.com/android/reference/com/google/android/gms/fido/Fido).
Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window fido-1.0.0-beta05.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.
