Why is my trackpad interfering with input after enabling keyd?

libinput, a higher level input component used by most wayland and X11
setups, includes a feature called 'disable-while-typing' that disables
the trackpad when typing.

In order to achieve this, it needs to distinguish between internal and
external keyboards, which it does by hard coding rules for specific
hardware ('quirks'). Since keyd creates a virtual device which subsumes
both external and integrated keyboards, you will need to instruct
libinput to regard the keyd virtual device as internal.

This can be achieved by adding the following to
/etc/libinput/local-overrides.quirks (which may need to be created):

[Serial Keyboards]

MatchUdevType=keyboard
MatchName=keyd*keyboard
AttrKeyboardIntegration=internal

Credit to @mark-herbert42 and @canadaduane for the original solution.
