Emacs text faces

from blog lmno.lol @alvaro, | ↗ original
Text faces = Text styles. Face attributes: font, height, weight, slant, foreground/background color, and underlining or overlining. Font lock mode automatically assigns faces to text. M-x list-faces-display: Shows faces defined. M-x helm-colors: Also handy. Unspecified attributes are taken from 'default' face.