I didn't know they were going to do this, but seeing it makes me very happy. The Southwest corner of the the PATH platforms cuts across the foundation of the original 1 WTC. They installed glass panels in the PATH platform giving you view of the original foundations below. A very nice touch, and means that nearly 100% of the 1 WTC foundations are visible. Here are some photos:
This shows which corner cuts through the PATH.
Source:
@andrewnathanson on Twitter