The status indicator light (SIL) on Mac mini, Mac Studio, and Mac Pro has different patterns based on the state of your Mac. These patterns also occur on some earlier MacBook, MacBook Pro, MacBook Air, and iMac models, though not all Macs have a SIL. If you have a Mac Pro, learn about the status indicator light behavior on Mac Pro (2023) or Mac Pro (2019).
I still wish Macs would show a pulsing LED when asleep. Even the machines listed in this document just show a solid LED when running and sleeping. I miss that little touch of useful whimsy.