nl_tokens: https : // dom . spec . whatwg . org / #notify - mutation - observers
pl_tokens: function notifyMutationObservers ( ) { mutationObserverMicrotaskQueueFlag = false ; const notifyList = [ ... activeMutationObservers ] . sort ( ( a , b ) => a . _id - b . _id ) ; activeMutationObservers . clear ( ) ; const signalList = [ ... signalSlotList ] ; signalSlotList . splice ( 0 , signalSlotList . length ) ; for ( const mo of notifyList ) { const records = [ ... mo . _recordQueue ] ; mo . _recordQueue = [ ] ; for ( const <mask> of mo . _nodeList ) { node . _registeredObserverList = node . _registeredObserverList . filter ( registeredObserver => { return registeredObserver . source !== mo ; } ) ; if ( records . length ) { try { mo . _callback ( records . map ( idlUtils . wrapperForImpl ) , idlUtils . wrapperForImpl ( mo ) ) ; } catch ( e ) { const { target } = records [ 0 ] ; const window = target . _ownerDocument . _defaultView ; reportException ( window , e ) ; } } } } for ( const slot of signalList ) { const slotChangeEvent = Event . createImpl ( [ "slotchange" , { bubbles : true } ] , { isTrusted : true } ) ; slot . _dispatch ( slotChangeEvent ) ; } }