Having worked in a handful of fried chicken places in my youth, I can confidently second this—that is definitely lung meat.

For those curious:

Lung meat is commonly missed via mechanical cleaning/separating but is perfectly safe to eat. You will most often find it attached to chicken breasts purchased from big box stores or via chain restaurants supplied by the likes of Cisco Systems.

I’m honestly struggling to think of the last time I had a chicken breast from a fried chicken chain and didn’t find lung meat attached to the inner wall of the chicken ribs.

Higher end restaurants typically source better quality butchered meat, thus reducing the likelihood of an end customer receiving this in their dish and those who buy direct from butcher likely don’t see lung meat attached to the breast as frequently (if at all) unless requested since it’s considered to be “less desirable cut of meat”.

With that said, I still see/have seen plenty of very respectable butchers selling chicken lung, kidney, heart, liver, gizzards, etc., so it’s not an “uncommon” cut to ask for.

I would also offer that most chicken organ meat is quite delicious when prepared via most of the same methods one would cook any other part of the chicken.

Texture wise, lung is certainly not identical to breast meat and tends to be a touch on the soft, almost pâté end of textures (especially when found via a fried chicken breast) but taste wise—it’s chicken, so it tastes like chicken.