qmk_firmware/keyboards/hhkb/keymaps/shela
..
action_pseudo_lut.c
action_pseudo_lut.h
config.h
keymap_jis2us.h
keymap.c
readme.md
rules.mk

Shela's HHKB Layout

Layer 0: US Layout
Layer 1: Pseudo US Layout
Layer 2: Dvorak Layout
Layer 3: Mouse
Layer 4: Tenkey
Layer 5: HHKB Fn Key
Layer 6: SpaceFN

Pseudo US Layout

On japanese Windows, HHKB Professional 2 US layout model recognized wrongly as JIS layout without changing OS settings.
But, you can use HHKB like a US layout keyboard as it is.