Blocking #9867 #9822 #9888 #9886 #9891 Optional: * #8685 Do we want to support `back` as a navigation type in the first version? * #8784 Reloads are disabled by default, should we enable them as an option in the first version? * #8785 * #9526 Resolved, still not in the spec: * #8677 Add the design principle of SPA/MPA compatibility as a note * #9156