Where does the purple edge or glimmer of LED light throw come from?

Hello, I have already been addressed to the Lila Schimmer or edge of the light cone by my LED headlights several times. Unfortunately, I couldn’t give a suitable explanation for this so far, except, “because the LED headlights are”. Google has so far thrown nothing out of me. Can anyone explain this to me here? At Xenon, a violet light points to a soon-to-be life. Here, however, it is only about the edge of the light cone.