The args in the event is gigantic, and it sends down an extension's complete state every time, even when a small thing like a console error was added to the extension.
The extension info also contains particularly expensive extension icon url/data url. Which also hits disk?

e.g. Running "for (i = 0; i < 1000; ++i) console.log(i);" from an extension while chrome://extensions tab is open easily takes 100%+ cpu on that tab's process on my machine.

There are various things we can do here to improve things. This bug will track that.

"Chrome Apps & Extensions Developer Tool" relies on developerPrivate, so we cannot make breaking changes or change the extension.