I believe I finally found the exact diagram and answers I was looking for. They're called mobile app visual flow charts.
Slight variation from flowcharts in @BennySkoberg answer.
Merging of wireframes with flows. As the above artifact mixes readable screens with flows or user actions, the element of time and
narrative begins to emerge. Since the flow diagram is inseparable from
the wireframe, it also saves the designer from the extra effort of
synchronizing multiple documents.
Transition references. Although not
visible in the sample, the blue circles are actual links to .mov files
that show short video demos of the transitions. Wires plus video feels
Screen references. All of the screens have an ID tag, and
occasionally actions lead to screen references instead of full screens
– a way of reusing and again minimizing duplication efforts. Also each
screen links to a folder with source PNG layout files.
Action references. Most user actions here also have an ID with a distinct
style and can therefore also be referred to.
Starting Point. Since the
canvas is quite large it has a clear starting point to guide the
Layout structure. In the top right of the canvas, the core
structure of the layout along with some popular components are
Toggle-able layers. Various information is kept separate on
distinct layers and so that it’s possible to toggle it on and off for
Screenshot taken from Anton Volkov's user flow chart on Wireframes Magazine.