An outfit worn by Sunday as an NPC, prior to becoming playable in version 2.8; he also wears this outfit in the Light Cone, After the Charmony Fall.
His original outfit consists of a grey shirt, long-sleeved white jacket, white gloves, earrings, white pants with a single white thigh belt on his left leg, and black shoes.
This tag implicates sunday_(honkai:_star_rail) (learn more).