Axial is a really pretentious label for something fairly simple — movement along a line. Axial hypertext isn’t strictly linear, though. Rather, readers are invited to take explore regular digressions from, then return to the main text.
Basically, this is how we write every piece of nonfiction on the web.
A feature story with some included image galleries? Axial hypertext.
A sidebar that expands over the main story, then shrinks back to its initial location when you’re finished? Axial hypertext.
A video embed that offers some additional context for the narrative? Axial hypertext.
A card stack at the end of a Vox article? Axial hypertext.
I could go on, but I think you get the point.