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 kmp-nativecoroutines-annotations-wasm-js-1.0.0-ALPHA-24-kotlin-2.0.0-Beta2.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.