JetBrains Marketplace ZIP Signer
· The main goal of the JetBrains Marketplace ZIP Signer is to sign and verify JetBrains plugins, but it can be applied to any other ZIP archive. The general concept of the used ZIP archive signature scheme is similar to APK Signature Scheme V2.
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 marketplace-zip-signer-cli-0.1.19.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.