This is a karabiner elements complex ruleset for DreymaR's extend layer. In other words, this allows you to use DreymaR's Extend Layer using the MacOS application Karabiner Elements, with some minor modifications for better usage on MacOS.
After downloading Karabiner Elements and giving it the required permissions, just paste this link into your browser. karabiner://karabiner/assets/complex_modifications/import?url=https://raw.githubusercontent.com/ProfXwing/extend-karabiner/master/extend.json
The following is an image of DreymaR's extend layer for reference.
My ruleset includes everything but the compose key, the break key, the menu key, and the print screen key. In addition, the Ctrl key is replaced with Mac's option key because the main usage is for text navigation. The Alt key is replaced with the Ctrl key.
The extend layer is activated by holding Caps Lock. If you just press Caps Lock, the key acts as usual. When the extend layer is activated, press any of the keys shown in the image above to use them.