The Experimental folder gains a bless-india-posters row, provisional until
its bundle is in the tree (a missing bundle prunes the row, so nothing shows
before it lands), with its label in all 11 locales. Its root is a
natural-height page of poster cards, so a row may set scroll: the element is
then mounted unpinned at its natural height and the pane scrolls it, instead
of being pinned to the pane, which would trap the page's own content.
check:posterverse-shelf expects the row and the scroll set by name; its
self-test drops the row and drops the flag.
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