Firefox has offered the same in the Aurora / Developer Edition channel since July 2014: https://hacks.mozilla.org/2014/07/event-listeners-popup-media-sidebar-cu

Firefox has offered the same in the Aurora / Developer Edition channel since July 2014: https://hacks.mozilla.org/2014/07/event-listeners-popup-media-sidebar-cubic-bezier-editor-more-firefox-developer-tools-episode-33/ https://hacks.mozilla.org/2014/07/event-listeners-popup-medi... More docs on MDN: https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Work_with_animations https://developer.mozilla.org/en-US/docs/Tools/Page_Inspecto...