Hey @Brendan_Christie, @Blokas’ Giedrius will give you the lowdown, but in the meantime here’s a thread on broken LEDs, including the part# and some internal pics.
(btw: I wouldn’t want to leave the impression that the LEDs are that fragile: all of my Midihubs have been really solid. But then again I have no tiny testers around!)
The Top LED does two main jobs; it lights up solid to show it’s on† and it blinks to show USB port traffic.
†(one of the 8 also lights to show which preset is active)