GNU Libtool
· GNU Libtool is a generic library support script that hides the complexity of using shared libraries behind a consistent, portable interface.
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 libtool-ndk26-static-2.4.6-beta-1.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.