I always use numeric keypad as arrows, as I find it more convenient than using an separate arrow pad. Until recently I used a tool Karabiner Elements, but it stopped functionning at Big Sur. Yes, The Karabiner developer is working on that issue, but it will be better to solve it without relying on a third-party tool.
It will be enough for me to either remap Xcode, or (which is preferred) to change key bindings in the system, using a tool like hidutil.
Xcode's Preferences - Key Binding has a section Text - Section. When I try to modify the binding for say Move Down by pressing Down arrow on numeric keypad it comes up as '2'. Now whereever I press '2', on keyboard or numeric keypad, it always works as Move Down which is certainly not what I am after.
About hidutil. I couldn't find a good manual or any example of keyboard mapping.
Any help?
Had another look at this article. Here is the answer:
hidutil property --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x70000005A,"HIDKeyboardModifierMappingDst":0x700000051},
{"HIDKeyboardModifierMappingSrc":0x700000060,"HIDKeyboardModifierMappingDst":0x700000052},
{"HIDKeyboardModifierMappingSrc":0x70000005C,"HIDKeyboardModifierMappingDst":0x700000050},
{"HIDKeyboardModifierMappingSrc":0x70000005E,"HIDKeyboardModifierMappingDst":0x70000004F},
{"HIDKeyboardModifierMappingSrc":0x70000005F,"HIDKeyboardModifierMappingDst":0x70000004A},
{"HIDKeyboardModifierMappingSrc":0x700000061,"HIDKeyboardModifierMappingDst":0x70000004B},
{"HIDKeyboardModifierMappingSrc":0x700000059,"HIDKeyboardModifierMappingDst":0x70000004D},
{"HIDKeyboardModifierMappingSrc":0x70000005B,"HIDKeyboardModifierMappingDst":0x70000004E},
{"HIDKeyboardModifierMappingSrc":0x700000062,"HIDKeyboardModifierMappingDst":0x700000049},
{"HIDKeyboardModifierMappingSrc":0x700000063,"HIDKeyboardModifierMappingDst":0x70000004C}]}'
Still can't fugure out, how to do (if possible) complex mapping with modifier keys (eg Ctrl+PgUp to Home), but that's another topic.