Can someone please explain binned and unbind in one sentence preferably?
Nearly all chip manufacturers will "bin" chips that have a defective component and sell it as another chip model that has that defective component disabled (it's standard practice in the industry, it greatly increases yields and prevents these chips from having to be thrown in the trash). The unbinned chip is the chip that has all of its components enabled, and the binned chip is the lower-tier model that is usually sold at a lower price.
In Apple's case, the binned chip has 5P cores instead of 6P cores, and 14 graphics cores instead of 18 graphics cores. Both chips were manufactured exactly the same way, the binned one just has some cores disabled.
Intel does this too. Typically the i3, i5, and i7 chips will all come from the same basic dies sent to the manufacturing plant (all chips are made to be i7s). Then they're all tested, and the best dies are sold as i7s with everything enabled. A chip that couldn't pass as an i7 might become an i5 (might have a small amount of cache disabled, have fewer cores, run at slightly lower clock speeds, etc. Just depends on the model), and so on.
Back in the day, people actually figured out how to re-enable the disabled core in some very old AMD 3-core processors. Often the core did actually work (AMD still has to meet orders and might bin some perfectly good chips to meet demand), and in cases where it did, you could get a quad core for the price of a 3-core. Nowadays chip manufacturers fuse the disabled parts off, so that's usually not possible today.