Emoji components are code points used to build other emoji. Most are not meant to be shown alone.
Skin tones are the only emoji modifiers. They are also emoji components because they are building blocks used inside finished emoji sequences.
Component groups:
Pre-Emoji 1.0 / E0.0 components include keycap parts, zero width joiner, variation selector-16, regional indicators A-Z and tag characters used by subdivision flags.
Emoji 1.0 components are the five Fitzpatrick skin tone modifiers: light, medium-light, medium, medium-dark and dark.
Emoji 11.0 components are the four hair components: red hair, curly hair, bald and white hair.