AccName algo (Name from Content section that covers pseudo elements) probably needs an update for ::marker, which—if I understand correctly—comes before ::before, but can also have another ::before::marker before ::before (but after *::marker), and an ::after::marker after the element contents but before ::after.

• https://www.w3.org/TR/css-lists-3/#marker-properties
• https://www.w3.org/TR/css-pseudo-4/#selectordef-marker