<dependency>
  <groupId>org.webjars.npm</groupId>
  <artifactId>acorn</artifactId>
  <version>6.4.2</version>
</dependency>

implementation 'org.webjars.npm:acorn:6.4.2'

implementation("org.webjars.npm:acorn:6.4.2")

libraryDependencies += "org.webjars.npm" % "acorn" % "6.4.2"

@Grapes(
  @Grab(group='org.webjars.npm', module='acorn', version='6.4.2')
)

<dependency org="org.webjars.npm" name="acorn" rev="6.4.2" />

[org.webjars.npm/acorn "6.4.2"]

'org.webjars.npm:acorn:jar:6.4.2'