Example 6.3.3 shows that some Austrians have advanced (presumably through an Attack order) into the reformation area of a deployed French infantry formation.
How does this happen?
The commentary bubble in the side column notes that this is not a situation that will occur often *because* the player threatened with overlap may shift Units to cover their exposed flank.
The point of the example (along with several of the subsequent examples) was to indicate what qualified as Grand Tactical Outflanking, 6.6.3 really doesn’t seek to explain how the French got themselves into that situation, just that, “if you look at the tabletop, and see this, yes, it qualifies”.
The most likely way the Austrian Units end up wrapping like that is that during Combat they win a handful of rounds with breakthrough results. Similar to example 6.6.4 but from the flank.