in extractor/src/main/scala/org/jetbrains/sbt/extractors/UtilityTasks.scala [173:180]
def librariesClassifiers(options: Options): Seq[String] = {
val buffer = new ArrayBuffer[String]
if (options.resolveSourceClassifiers)
buffer += Artifact.SourceClassifier
if (options.resolveJavadocClassifiers)
buffer += Artifact.DocClassifier
buffer.toSeq
}