You can run a locally hosted development version of the web app within the Konvergo (code name for what became Plex Media Player) application. If the main app window is open you can also run Chrome side by side to debug.

• Run the grunt server:konvergo from the web-client submodule. This will run a dev version of the web client
• Update the starturl in ~/Library/Application Support/Plex Media Player/Plex Media Player.conf to point to http://localhost:3333/app/dev-konvergo.html
• Run the Plex Media Player.app
• Tail the ~/Library/Logs/Plex Media Player/Plex Media Player.log, optionally grepped with WebClient to see console.logs
• Open Chrome and point to http://localhost:3333/app/dev-konvergo.html. This should open a Qt channel to the main Plex Media Player.app and function as normal - but with the ability to add breakpoints and inspect code