The idea is to disable default compile execution and introduce our own to get control over the order in which goals are executed, so that we could run kotlin compiler before java compiler.
See this PR Add maven example without using process-sources by ansell · Pull Request #458 · JetBrains/kotlin-web-site · GitHub for details.
Also is it possible to replace the version string of the plugin with a generic maven property to denote the current version of maven?
I’m not sure which plugin do you mean, but usually each plugin in maven gets its own versioning which isn’t aligned with the versioning of maven itself.