• packages/react-devtools-extensions/src/background/dynamicallyInjectContentScripts.js
• packages/react-devtools-extensions/src/background/index.js
• packages/react-devtools-extensions/src/background/injectProxy.js
• packages/react-devtools-extensions/src/background/setExtensionIconAndPopup.js
• packages/react-devtools-extensions/src/background/tabsManager.js