You will also miss a lot hints about the odd things that happen around the On/Off star - almost as if there was something different about that volume of space...
Maybe I missed something about the location, but I thought the On/Off star was just inside the Beyond, where a lot of advanced technologies start working, and had the remnants of a Beyond civilization (including antigravity materials)?
The actual On/Off star was presumably powering a zone changing device of some kind - antigravity technology had remained working for millions of years which made me think it was in a bubble of High Beyond or Transcendent zone levels (like the ending of AFUTD).
They did also say in AFUtD that the Zone boundary isn't smooth and continuous, it's like a foam with ripples and bubbles near the boundary and moves around some normally -- which is why ships that ply the Low Beyond near the Zone boundary always carry coldsleep units and ramscoops as a backup.
Did we every get an in universe or author-commentary explanation confirming the theories about the On/Off? I always figured it was some high-tech artifact based on Beyond or Transcend tech that was going to remain mostly unexplained?
In-universe, there's a conversation between a couple of the focused near the end of chapter 15. One of them speculated that it was a fast square wave generator.
Discussed up-thread: OnOff has an eccentric orbit, and I think we're meant to infer that it was in the Beyond or Transcend at one point. (I think the characters draw the wrong conclusion about which part of its eccentric orbit was the interesting one and we're meant to read it as horribly ironic that they're planning on going entirely the wrong way. But someone else concluded from Fire that the galactic core also had interesting activity.)
