The GoogleUtilities pod is a set of utilities organized into CocoaPods subspecs. See the podspec for a summary of what utilities are currently included. They're used by Firebase and other Google products.
Direct usage by non-Google products and CocoaPods is NOT currently recommended or supported in general.
However, we do specifically recommend that non-Google SDKs can use the App Delegate Swizzler to hook into app delegate methods as this reduces conflicts with multiple SDKs trying to do the same.
Instructions on how to adopt the app delegate swizzler for use by your SDK are available here.
Follow the subsequent instructions to develop, debug, and unit test GoogleUtilities:
$ git clone git@github.com:firebase/firebase-ios-sdk.git
$ cd firebase-ios-sdk/GoogleUtilities/Example
$ pod update
$ open GoogleUtilities.xcworkspace
Choose the one of the Tests* schemes and press Command-u.