tunnel in ceiling

I didn't see any photos taken of the deep part of this tunnel anywhere online. Though it couldn't be seen while I was taking the picture, there appears to be some kind of ladder further up. This is a focus stack of two images. I lit it with a flashlight, but it couldn't reach far enough. The distant light is natural, so there's an entrance over a hundred feet above. However, I've walked all the normal trails without finding it. It may be in an inaccessible cliff.

Done