Reading order defined
This GreenLight check makes sure that the reading order has been set with GreenLight, CircularFLO, or the InDesign Articles panel.
“An EPUB consists of multiple resources that can be completely navigated and consumed by a person or program in some specific order.”
From EPUB 3 Overview - 1.2.1 Reading Order
https://www.w3.org/publishing/epub/epub-overview.html#sec-nav-order
While many reflowable publications have an obvious reading order, or logical progression through their content, fixed-layout publications may be more complex in their design and layout and may consist of multiple readable objects on the same page.
The specific order that these objects are read in, and the order in which they will be read aloud by ebook readers and assistive technology, can be vital for the understanding of the publication.
Use the CircularFLO and GreenLight Reading Order tools to define and modify the reading order of InDesign objects.
This check will skip invisible objects (including object on a hidden layer), objects on a Parent Page and text frame that contain only a single number.
