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 opensslAndroidNativeArm64Binaries-OpenSSL_1_1_1q_a.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.