I have been there. It was exceptionally dim/dark I couldn’t see anything. I know I was five feet away from the wall with a niche where Peter’s bones is.

The story was that the original church was built by Emperor Constantine on top of Peter’s tomb. When the basilica was built about a thousand years later. Peter’s bones were moved to its current location a few hundred yards away.

This video gives a glimpse of the jeweled box and Peter’s bones. https://youtu.be/DhnJgAzSHD8