Here are the classes, structs, unions and interfaces with brief descriptions:

CatNiPAppDelegate
CatNiPViewController
DetailPopoverController
IMSLPCompositionData
IMSLPDelegateDataSource
IMSLPQueryHelper
IMSLPScoreData
LocalCompositionData
LocalDataHandler
LocalDelegateDataSource
LocalScoreData
MediaWikiCategoryQuery
<MediaWikiCategoryQueryDelegate>
MediaWikiDownload
<MediaWikiDownloadDelegate>
MediaWikiPageQuery
<MediaWikiPageQueryDelegate>
MediaWikiQuery
<MediaWikiQueryDelegate>
NotesPopoverController
PlaylistsDelegateDataSource
ScorePopoverController
UIDocumentObject
UIScoreView
UIVerticalScrollBar