{{REVISIONID}} can be used to adapt a template behavior, depending on edit or read mode. An example is here (user sandbox pages control) and here (user sandbox subpage) where the {{user sandbox+}} template adapts on edit, in both pages. Lately this functionality broke in the VisualEditor and is only functional in the old source editor, or after switching from source to visual, due to caching of the template during reading the page. Can __NOCACHE__ help restore such template functionality?
