Browsers ship with their own developer tools. These are amazing tools to help you debug your web application. Consider learning how to use them.
Once you have your local installation of Forem running, you can attach to either the Chrome or Edge Debugger.
If you do not see your editor here, consider contributing to the documentation. 😉
Preact has their own developer tools in the form of a browser extension. The Forem codebase is configured out of the box to support the Preact Devtools.