7 Loading web pages7.1 Supporting concepts7.1.1 Origins7.1.1.1 Sites7.1.1.2 Relaxing the same-origin restriction7.1.2 Origin-keyed agent clusters7.1.3 Cross-origin opener policies7.1.3.1 The headers7.1.3.2 Browsing context group switches due to cross-origin opener policy7.1.3.3 Reporting7.1.4 Cross-origin embedder policies7.1.4.1 The headers7.1.4.2 Embedder policy checks7.1.5 Sandboxing7.1.6 Polic