Replay is developing a time-travel debugger for JavaScript that records everything in a browser, facilitating debugging without being tied to specific frameworks or libraries. The integration of React DevTools (RDT) within Replay allows users to inspect component trees and states in React applications by capturing the necessary data during the recording process. Initially supporting Firefox, Replay aimed to bring feature parity to Chrome by incorporating RDT support using "Replay Routines," a novel runtime analysis technique. This approach allows for capturing and analyzing the behavior of applications at any given point, treating runtime behavior as queryable data. The React DevTools consist of a backend logic injected into web pages and a UI component for rendering component trees, which was adapted to work with Replay’s time-travel debugging API. The integration involved modifying the RDT backend to work with Replay's analysis APIs and browser forks, ultimately leading to a successful implementation that supports enhanced debugging capabilities for React applications in Chrome, with plans to extend support to Redux DevTools and other frameworks.