Well, this is supposed to be general base map for everyone, not a chimera to accommodate specific workflows for everyone. Now that Blender no longer has predefined 20 layer bits, but actual proper layer system that most people will name alphabetically, keyboard number switching of layers doesn’t make much sense to be honest. It’s kind of “side effect” workflow from the old times when Blender’s layer system was limited. Sure, you can still utilize it that way, but what that probably means is that you are not using the new collection system to its full potential.
With that said, I’ve added them on numpad 0-9 keys since they were completely empty, and many laptops don’t even have numpad so some people won’t even be bothered by them. But I still think that switching layers using predefined amount of keys with predefined order is a clumsy workflow.
To update, just redownload the file and import the keymap again, and it should work 