When is the second point fulfilled? Can anyone give an example of such a case?

The question is directly related to the explanation from the specification:

Elements are pushed onto the backup element queue during operations that affect the DOM without going through an API decorated with [CEReactions], or through the parser’s create an element for the token algorithm

If the parsing case is simple, then it is very difficult to understand which APIs are not decorated with [CEReactions] that affect the DOM; I was not able to figure this out. Does anyone know these APIs that are not decorated with [CEReactions]?