apply_filters( 'riff_cover_accent', bool $on )

Filters whether the player takes its accent from the cover of the track playing: the cover's hue, muted and lightened until it reads on the player's dark surfaces, as --riff-cover-accent, on the seek bar, the playing bars, the current Up next item and a wash behind Now Playing, and in the Listen app's own document on its links, the track playing, Liked songs and the Browse tiles. A cover that is grey, near black or near white gives none, and the accent is the site's --riff-accent, as it is everywhere with this off.