It's the intercostal muscles I believe. Really difficult to cook, it's slightly dry despite being marinated and doesn't have a sheen unlike the other meats once u cook it. Kinda sticks to the grill. Ideally it's seared on all sides without overcooking the interior, but I ended up undercooking the interior for some pieces(they are not uniformly thick).

Not to mention it curls up and twists, making it even harder to cook each surface properly.

By right there's quite a lot of flavour, but only if u do it right. I'll advise only order if you know what you're doing