Including custom files in JS library

If you configure binaries.library() in js(IR), the build will produce build/productionLibrary/ with the files needed to publish the library to NPM. The package.json in it can be customized. However, NPM packages typically also include README, LICENSE and potentially other files. Can these be added to the package without configuring a custom copy task?

js(IR) {
      // ...
      compilations["main"].packageJson {
          customField("foo", "bar")
      // Something like this:
      compilations["main"].files(files("", "LICENSE.txt")) // Does not actually compile.