It was moved to a double tap on Shift, see https://github.com/OneDeadKey/zmk-config-aekeynox/commit/96f7f22ac34059b63d3bf01d5afff7387d843d07. The website keymap is no longer up-to-date.
It was moved to a double tap on Shift, see OneDeadKey/zmk-config-aekeynox@96f7f22. The website keymap is no longer up-to-date.