Here's a list of custom bones you can edit with ABMX and modify with ABMX for expressions:

cf_J_CustomBones
cf_J_Custom_Dimples00_S
head nose *side* d.L
head nose *side* d.R
cf_J_Custom_CheeksLower_S
head cheek *side* c.L
head cheek *side* c.R
cf_J_Custom_Dimples01_S
head nose *side* c.L
head nose *side* c.R
cf_J_Custom_Nostrils_S
head nose *side* b.L
head nose *side* b.R
cf_J_Custom_Nosetip_S
head nose middle
cf_J_Custom_Nosebridge_S
head nose *side* a.L
head nose *side* a.R
cf_J_Custom_UpperCheek00_S
head cheek *side* a.L
head cheek *side* a.R
cf_J_Custom_UpperCheek01_S
head cheek *side* b.L
head cheek *side* b.R
cf_J_Custom_Forehead_S
head forehead *side*.L
head forehead *side*.R
cf_J_Custom_Eyebrows_S
head eyebrow *side* a.L
head eyebrow *side* b.L
head eyebrow *side* c.L
head eyebrow *side* a.R
head eyebrow *side* b.R
head eyebrow *side* c.R
head eyebrow middle
cf_J_Custom_EyelidUpper_S
head eyelid upper *side*.L
head eyelid upper *side*.R
cf_J_Custom_EyelidLower_S
head eyelid lower *side* a.L
head eyelid lower *side* b.L
head eyelid lower *side* a.R
head eyelid lower *side* b.R
cf_J_Custom_Jaw_S
cf_J_Custom_Tongue00_S
tongue00
cf_J_Custom_Tongue01_S
tongue01
cf_J_Custom_Tongue02_S
tongue02
head jaw
cf_J_ScalpLength_S
cf_J_CustomMouth
cf_J_Custom_LipsUpper_S
head lip upper middle
head lip upper *side*.L
head lip upper *side*.R
cf_J_Custom_LipsLower_S
head lip lower middle
head lip lower *side*.L
head lip lower *side*.R
cf_J_Custom_LipsSide_S
head lip corner *side*.L
head lip corner *side*.R