=== What steps will reproduce the problem? ===
Look for example at "sortWith".
=== What is the expected behavior? ===
Usage of internet slang should be replaced by a more formal wording.
=== What do you see instead? ===
That is, elements that are equal wrt lt appear in the same order in the sorted sequence as in the original.
I guess "wrt" means "with regard/respect to".
Maybe it would be better to replace these kinds of expressions by better wording. (I think grep'ping through the source might reveal a lot of these internet terms in other files, too.)
Additionally, the parens around "wrt lt" got eaten by ScalaDoc and the deprecated "sort" method has broken "=>"s in the documentation.