Different openapi.jar in Maven Central and IntelliJ CE

I've noticed that idea-IC-141.1532.4/lib/openapi.jar does not appear to contain the same classes as the one from http://mvnrepository.com/artifact/com.intellij/openapi

In particular the former contains com.intellij.util.PlatformUtils and the latter doesn't.

elharo@elharo:~/.gradle/caches/artifacts-23/filestore$ jar tvf IntelliJ/idea-IC-141.1532.4/lib/openapi.jar  |grep Platform
  2015 Thu Jun 18 22:45:04 EDT 2015 com/intellij/patterns/PlatformPatterns$1.class
  3486 Thu Jun 18 22:44:46 EDT 2015 com/intellij/patterns/PlatformPatterns.class
  6578 Thu Jun 18 22:44:46 EDT 2015 com/intellij/util/PlatformIcons.class
  3084 Thu Jun 18 22:44:46 EDT 2015 com/intellij/util/PlatformUtils.class
   346 Thu Jun 18 22:44:48 EDT 2015 com/intellij/util/PlatformUtilsCore.class
  2331 Thu Jun 18 22:48:12 EDT 2015 com/intellij/openapi/externalSystem/service/project/PlatformFacade.class
  4546 Thu Jun 18 22:47:14 EDT 2015 com/intellij/openapi/actionSystem/PlatformDataKeys.class
  1228 Thu Jun 18 22:47:10 EDT 2015 com/intellij/openapi/wm/StatusBarWidget$PlatformType.class

elharo@elharo:~/.gradle/caches/artifacts-23/filestore$ jar tvf com.intellij/open*/*/jar/*/*jar|grep Platform

elharo@elharo:~/.gradle/caches/artifacts-23/filestore$ ls com.intellij/open*/*/jar/*/*jar
com.intellij/openapi/7.0.3/jar/5d93ad6b315b8a88b9e742f58ecef1f673c12823/openapi-7.0.3.jar

I'm pretty sure there are a lot of other classes missing as well.

Is there a reason fro this discrepancy? Are there Maven artifacts that do provide the full complement of IntelliJ classes? I'm trying to create a gradle build for an IntelliJ plugin.