WAR
A WAR archive allows you to easily deploy your application inside your web container / servlet container, by just copying it to its folder. Ktor supports two popular servlet containers: Jetty and Tomcat. It also serves when deploying to google app engine.
Xml
This gradle buildscript defines that you can use to run your application.
note
In the case where you only need to generate a war file, there is a task defined in the war plugin.
Just run and it will generate a file. For a full example: