Where the shape comes from
Long hair, built from 長, long, combined with the fine parallel strokes for flowing strands — hair grown out and left to move rather than cropped close. It once headed 髮, hair itself, before simplification folded that character into 发, unrelated in origin, meaning to send out, emit, one of the language’s more famous collisions of two old words into one new shape; and it survives clearly in 鬓, the hair at the temples.
汉字 filed under 髟
No published character on HSK Guide is filed under this radical yet. 汉字库.