We propose to perform X-ray magnetic circular dichroism (XMCD) measurements on Mn-doped graphene, as an extreme model case of multi-channel Kondo effect, which in turn is one of the most challenging problems in condensed matter physics today. Combined with state-of-the-art numerical renormalization-group (NRG) calculations, implementing a three-band NRG model, this XMCD experiment will allow us to reach the deepest understanding of Kondo physics in graphene to date.