DOM Mutation Events, including `DOMSubtreeModified`, `DOMNodeInserted`, `DOMNodeRemoved`, `DOMNodeRemovedFromDocument`, `DOMNodeInsertedIntoDocument`, and `DOMCharacterDataModified` are deprecated (
w3c.github.io/uievents/#legacy-event-types
) and will be removed. Please use `MutationObserver` instead.