What is a silicon interposer?

Other than standard coffee shop among friends here in Silicon Valley, since it was mentioned in the keynote and is part of the “secret cause” that makes the M1 Ultra work, here’s a link that I think is a good overview:


@SpivR you are now more valuable to me than google. Not only did you find the right information, you presented it to me before I had to type my search into a text box.