in aws-codepipeline-agent/src/main/java/jetbrains/buildServer/codepipeline/CodePipelineBuildListener.java [138:140]
private File getInputArtifactFile(@NotNull File inputFolder, @NotNull String s3ObjectKey) {
return new File(inputFolder, new File(s3ObjectKey).getParentFile().getName() + CodePipelineUtil.getArchiveExtension(s3ObjectKey));
}