@peanut Oh, they're not connected in any fancy way at all. Since the Omega has the PHY, and since there's no broken-out pins specifically for the LEDs, I wired them up to GPIO15 and GPIO16. They function in that I can light them up by flipping them high as GPIO's, but I haven't gone farther than that yet.
My understanding is that I can tweak the device tree a bit to say "No, this isn't a GPIO pin, it's an LED that is controlled by a GPIO" and then "This isn't just an LED, it's an LED that needs to be connected to an LED trigger that comes from the eth0 link status". The kernel handles it from there.
There are LED's in many routers connected in the same way, it's just a matter of messing with it, and since the DTB appears to be baked into the firmware, I think that means rebuilding the firmware. Pretty low on the list of things to do at the moment.
In case you're wondering, there are two other LEDs. One is just a general-purpose indicator. The other comes on when the 12V output MOSFET is turned on. I left that one unpopulated, but I had a little room there, and wanted to play with a reverse-mounted LED shining through the FR-4 circuit board. If you look carefully, there's text in the layers of the board, which should get silhouetted by the LED.
Place on Github that has schematic PDF (and I don't know why I can't direct-link to the PDF)