This is the iOS SDK for the Dropbox Sync API.
A tutorial for installing and using Dropbox.framework can be found here.
You can find an example app that uses the SDK to edit notes in the Examples folder. Open ./Examples/Examples.xcodeproj to view and run.
You can install the Xcode docset by running the following command from this directory:
cp -R com.dropbox.Dropbox.docset ~/Library/Developer/Shared/Documentation/DocSets
Then restart Xcode to complete the installation.