True for a slideshow tour document: a v2 AnnotationCollection or a v1
AnnotationPageSequence carrying the matching extension context (never a
P3 Manifest/Collection), with items shaped like tour annotations.
Narrow by conjunction so P3 seeAlso collections never match.
Read a slideshow tour (W3C AnnotationCollection + extension) as storymap data — the counterpart of
manifestToStorymapData()for that format. Pure, so the same document always produces the same story.