The order of the koans in the exercises doesn't match the order listed in Finding Your Path (http://www.scalakoans.org/finding-path).
AboutLiteralBooleans/Numbers/Strings occur near the end of Koans.scala, but they're very close to the beginning of FYP. AboutLiterals is also included in FYP, but it could probably be omitted since it's all of the type-specific koans in a single file (but the explanations aren't as good).
There's a comment at the top of AboutCaseClasses that says "Case classes are also an integral part of pattern matching which will be the subject of a later" (sentence ends), but AboutPatternMatching occurs directly before AboutCaseClasses in the exercises and in FYP.
AboutEmptyValues explains Option.getOrElse but AboutOptions (which occurs a lot earlier than AboutEmptyValues) does not.