{# The navbar's bookmark slot. Rendered into the shell with whatever mark the worker holds, and returned on its own by api/bookmark after a write. Both paths must produce the same element for the swap to be seamless. Always filled: getBookmark() answers with the default when nothing has been set and when storage cannot be read at all, so there is no empty state to render. There was one -- a hidden slot that fetched itself once a worker turned up -- for pages boot.html composed before there was a worker to ask. Nothing composes a page but the worker now, and the worker always knows. #}