Things that need to be initialized per tab. Lazy-loaded tabs were till backed by about:blank content window which get replaced with the actual content once you

Things that need to be initialized per tab. Lazy-loaded tabs were till backed by about:blank content window which get replaced with the actual content once you open the tab. And with that about:blank comes overhead, which is fairly small for a single tab but it adds up in large numbers. The change is that now the tab item does not have an associated content window at all until you visit it.