Not OP but probably just the key next to the "’ key. The text on keycaps are just labels and do not dictate what the key does.

If you follow the github link (https://github.com/codybloemhard/eliza) you will find a picture of the matrix! I really like the upside down mods for space bars. It depends a bit on how you angle your hands when you type, but if I put the ‘space bar’ modifiers in their regular orientation, the edge will dig into my thumb. One thing I would do differently is the position of the screws. Two of the screws are right where my thumb comes down on the board when I press down the space bars. This was slightly irritating and I had to get used to it.

Haha. They are themed after ASCII control characters. ‘BS’ stands for ‘backspace’. Maybe you’ll like the ‘F_ack’ key as well :)

https://en.wikipedia.org/wiki/Control_character

‘stash’ is a command for the software ‘git’ which is something programmers use a lot. This GMK set has its modifier keys themed after that software. So the functionality of the keys is not really connected to what the text reads on them. In my case they happen to be shift and space.

Can’t imagine using full spacebar again after tasting split spacebars and 40’s. I’m never typing with 9 fingers again.