Missed the opportunity to put a golden watch on that picture.

Literally how I play chess, can’t be bothered to do math and just doing gut feeling… I think we need an full rules revamp for chess!

Wait that’s not an April’s fool joke?

Yup looking at the components around and the layout, it does look like a quartz crystal, especially considering it’s right next to the microcontroller, and the 2 beige components above are the matching capacitors.

But yeah I’ve never seen a package with an open window. Maybe it’s an ultra high precision that has been tuned with lasers (usually done for patch antennas).