docs: function getMatchingElementFromMutation  (mutation, selector)
  {
  	let {
  		type,
  		target,
  		addedNodes
  	} = mutation;
  
  	if (type === 'attributes' && target.matches(selector))
  	{
  		return target;
  	}
  
  	if (type === 'childList')
  	{
  		for (let addedNode of addedNodes)
  		{
  			if (typeof addedNode.matches === 'function' && addedNode.matches(selector))
  			{
  				return addedNode;
  			}
  		}
  
  		return target.querySelector(selector);
  	}
  
  	return null;
  }