Localization in Xcode is handled with NSLocalizedString, but it is such a verbose and legacy-like API. There’s a Swiftier way that still respects Xcode .xliff exports and comments.
The native mobile app version is available and was inspired from uncovering the joys, pains, and realities of mobile, web, and software development. Many of my blog posts dissect the very same app and other real-world projects. The best part – it is completely open-sourced in Swift!