Publish

In AEM, the instances that serve the public site — read-only copies of the content Author has activated to them, usually several behind a dispatcher, holding no editor and no authors; activating a page is the act that replicates it from Author to Publish

What brand-gate measures is a Publish page as the dispatcher serves it, which is the only version a visitor ever sees. Publish runs the same component bundles as Author with the authoring surfaces switched off by configuration, so a rendering difference between the tiers is a configuration finding, not a code one. Scaling a site is adding Publish instances; scaling authoring is not possible that way, which is the asymmetry the two-tier shape is built around.