{stack 'name'} prints the text that {push} tags added to the stack of that name, in the order they were pushed. The tag itself only prints a marker; the marker is filled in once the whole page has rendered. So a {stack} in the wrapper's <head> gets the pushes of every component further down, and a stack below a push and a stack above it get the same text.

A stack nothing was pushed to prints nothing. From PHP, padStackPush ( 'scripts', $html ) adds to a stack like a {push} does. A {stack} without a name is an error under the strict check.

{toc} works with the same kind of marker, filled in after the page has rendered.