qmk_firmware/keyboards/monarch/rules.mk

# Build Options
#   change yes to no to disable
#
BOOTMAGIC_ENABLE = no       # Enable Bootmagic Lite
MOUSEKEY_ENABLE = yes       # Mouse keys
EXTRAKEY_ENABLE = yes       # Audio control and System control
CONSOLE_ENABLE = yes        # Console for debug
COMMAND_ENABLE = yes        # Commands for debug and configuration
NKRO_ENABLE = yes           # Enable N-Key Rollover
BACKLIGHT_ENABLE = yes      # Enable keyboard backlight functionality
RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
AUDIO_ENABLE = no           # Audio output
SLEEP_LED_ENABLE = yes
ENCODER_ENABLE = yes

# Enter lower-power sleep mode when on the ChibiOS idle thread
OPT_DEFS += -DCORTEX_ENABLE_WFI_IDLE=TRUE