A node on the inner side of a key's handle, preventing the key from hanging vertically; bow bump.
It is not a random protrusion or adornment. It is called a swingress and has a precise function. While all ordinary keys will hang perpendicular to the ground on a bundle ring, swingress-equipped keys will undeviatably veer asymmetrically and incline to a slanted position. (Source: J∙ Okram - The Mystery of the Rammed Key.)
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