kotlinx.html
· A kotlinx.html library provides DSL to build HTML to Writer/Appendable or DOM at JVM and browser (or other JavaScript engine) for better Kotlin programming for Web.
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 kotlinx-html-linuxx64-0.9.1.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.