js-tracker

Not entirely right, though I do love the Perf tab. (Disclosure: I work on it.) This extension adds instrumentation to listen to changes to DOM nodes and style attributes. And it reports exactly what the change was: https://github.com/pilagod/js-tracker/blob/master/src/tracke... That level of detail isn't really provided in the Perf tab, as it's quite invasive and can have significant perf overhead in a busy webapp. (DevTools does have a hidden experiment called "Timeline: Invalidation Tracking" which does report on various DOM/CSS changes, though. It's cool). Also, I should point out a _very_ similar extension my mate built: https://github.com/kdzwinel/DOMListenerExtension Same basic idea, but just reporting every change to DOM nodes that a MutationObserver can see.