How to download and view legacy documentation from Apple (no need to sign in to your dev account).
- Go to https://developer.apple.com/library/downloads/docset-index.dvtdownloadableindex
- Find the docset you want (there are some with URL https://apple.com/none.dmg; ignore them - you will find them again further down the file with a working URL).
- Download the dmg. It's probably around a gigabyte or so.
- "Install" the .pkg file somewhere on your disk. If you don't trust the installer, do it manually:
- Find the largest file, names Payload, and extract it using The Unarchiver.
- This created a new, even larger file, probably named Payload-1.
- Extract Payload-1 using The Unarchiver.
- After many minutes of extracting, we have our .docset file.