“What’s interesting here is that all seven of these are M-class stars, and as the authors note, M-dwarf debris disks are quite rare, with only a few confirmed.”
Project Hephaistos ran Gaia, 2MASS and WISE data on about 5 million sources and kept seven stars with excess mid-infrared heat. All seven are M dwarfs. The proposed next step is optical spectroscopy to rule out false debris disks. Seven unexplained warm red dwarfs is an astrophysics problem, and the headline is the alien one.