The node is in the process of being destroyed. Calling QI on the node is not supported, however it is possible to get children and flags through nsINode as well as calling IsNodeOfType(eCONTENT) and casting to nsIContent to get attributes.
NOTE: This notification is only called on observers registered directly on the node. This is because when the node is destroyed it can not have any ancestors. If you want to know when a descendant node is being removed from the observed node, use the ContentRemoved notification.
Implemented in nsXULTreeBuilder.
Referenced by nsXULTreeBuilder::NodeWillBeDestroyed().