Dash for iOS is an open source tool allowing you to view over 150 API documentation sets offline on your iPhone and iPad from Kapeli.
Dash for iOS has a very clean interface with built-in searching. Included within the 150 documentation sets are iOS, watchOS, tvOS, macOS and Swift documentation. You can also generate your own docsets.
Here’s an image showing Dash for iOS in action from the homepage:
You can find Dash-iOS on the homepage.
A great open source tool for browsing and searching through iOS documentation.