The 30 pairs cover three concept families:
| Family | Examples | Count |
|---|---|---|
| Foundation value-type vs NS-class | URL/NSURL, Data/NSData, Date/NSDate, UUID/NSUUID, URLSession/NSURLSession, FileManager/NSFileManager, DateFormatter/NSDateFormatter, Bundle/NSBundle, Calendar/NSCalendar, TimeZone/NSTimeZone, Locale/NSLocale, Predicate/NSPredicate, AttributedString/NSAttributedString, Measurement/NSMeasurement and others | 27 |
| Swift stdlib vs NS-class | String/NSString, Array/NSArray, Dictionary/NSDictionary | 3 |
For each pair the query is the modern name as a developer would type it. The expected hits are documented as exact-URI patterns (apple-docs://foundation/url vs apple-docs://foundation/nsurl, etc.), verified to exist in the v1.2.0 candidate DB before the corpus was finalised.