This is very exciting! Is the corridor a dead end? Could it be only a relieving chamber? Are there any more photos, I can't find any.

It has been known since 2017 that there are voids in the Pyramid, and this was one of them. It will be exciting to see what is the big void on top of the grand gallery. Or is this tunnel connects to it. Or if they can get more evidence of the theorized internal ramp!