The main change here is that it changes signing for debug builds so that you don't need to sign up for an iCloud account. This also greatly simplifies development since it means you're not carrying around an uncommitted change to this setting (which makes certain version control operations really annoying). When creating a release this setting will have to be changed (but not committed) to whichever account is in charge of signing for the App Store.
The other changes are based on XCode recommendations (strip dead code, only build debug builds for the architecture being tested, and build different targets in parallel).
The main change here is that it changes signing for debug builds so that you don't need to sign up for an iCloud account. This also greatly simplifies development since it means you're not carrying around an uncommitted change to this setting (which makes certain version control operations really annoying). When creating a release this setting will have to be changed (but not committed) to whichever account is in charge of signing for the App Store.
The other changes are based on XCode recommendations (strip dead code, only build debug builds for the architecture being tested, and build different targets in parallel).