They are not related to IBKR. IBKR will simply pass exchange rebates to you, when you get any. I don't care for them, but sometimes see them as negative commissions on my trades, which is nice.
when you buy the ask you take liquidity when sell the bid you take liquidity. because the market is illiquid or something. this rebate thing is kind of stupid IMO> there used to have prop firms who specially on rebates from the exchange. mostly for HFT. business model does rebates matter.
Just like with any business, you study, search, research, read exchange documentation, search these forums, search for info online, learn how to trade to get the rebates, and decide whether it’s worth it. I think most people want good price on their trades, not get into business of trading for rebates.