Which file? What is the right command to enter to it?
Since this is still the top search result I'll post here. The keymap editor is an addon in kodi under program add-ons in the repository.
Edit > Global > Navigation > context menu > edit key > press the key you want to use.
I've tried onn 4k pro, raspberry pi5, and used the onn remote with a flirc on my htpc and it seems like by default long-pressing "select" will bring up the context menu, as well, without needing the keymap editor.
I've paired a 2nd gen 4k Firestick's remote to the pi5. I have an Insignia FireTV where the backlight went out so tried pairing that remote. I was successfully able to map the Guide button to open the Live TV guide in kodi (I use serverwmc). Unfortunately, the menu, channel up and down, and app switcher buttons all register as the same key press (61952), so you can only use one of them. Since I'm used to the menu button for context menu I mapped that key, and mapped long-press on the menu key to take screenshots.
For most people with a modern TV the pi should work out of the box via HDMI-CEC with your TV's remote. My pi5 is connected to an older soundbar, so I'll probably stick with the 4k stick's remote since it's already paired via infrared for power and volume. In my case it just occurred to me that I could connect the pi5 directly to the TV, which definitely does not have CEC, then connect the pi5 to the soundbar via bluetooth and control the volume that way.
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