[prablenha]

In their effort of calling it a line they made it complicated to see. They should've just highlighted the zone or something.

[80386]

Here: https://i.imgur.com/IOenPsu.png

[enriquto]

But this image has less information. What about the boundary between south Italy and Greece, that are delimited by the blue line?

[80386]

It doesn't exist. Southern Italy and Greece are both outside the Hajnal region.

[enriquto]

And then why is this boundary drawn on the wikipedia article?