At the WWDC 2023, Apple introduced the containerRelativeFrame view modifier to SwiftUI. This modifier simplifies some layout operations that were previously difficult to achieve through conventional methods. This article will delve into the containerRelativeFrame modifier, covering its definition, layout rules, use cases, and relevant considerations. At the end of the article, we will also create a backward-compatible replica of containerRelativeFrame for older versions of SwiftUI, further enhancing our understanding of its functionalities.