k_prefix, there is no much about them other than the fact that you have independent keys for lower and upper case letters, and other symbols that would require to shift in a normal keyboard, here you can have them as a key on their own, no shifting needed.
k_empty, a special key that does nothing.
m_prefix and act like modifiers in a normal keyboard: you hold it and then press some other key to modify it.
Ctrl + cin a single key press.
escapewhen tapped (pressed and released quickly) but will behave as
Ctrlwhen you hold it and press some other key at the same time. This one is particularly useful.
m_click_. The common ones being:
speedis number between 0 and 15 to describe how fast the pointer should move.
Layer Lockkey (
c_layer_lock) allows you to lock in the current layer and release the lock when pressed again.
c_flash_modekey in one of your layers. When pressed the keyboard will enter Flash mode and be ready to receive a firmware update.