Another report says "In addition, Kane said that although the planet has roughly three times the mass of Earth, the team calculated its density to be the same as our planet. "This is surprising because you'd expect the density to be higher," Kane said. "This is consistent with the notion that the planet is extremely old." The older a planet is, the less dense it's likely to be because not as many heavy elements were available when it formed, explained Kane. Heavy elements are produced by fusion reactions in stars as they age. Eventually stars explode, dispersing these elements from which new stars and planets will form.",
https://phys.org/news/2021-01-super-earth-galaxy-oldest-stars.html
[My observation. Finding rocky exoplanets orbiting very old stars with low metal content is surprising. Our galaxy's gas at 10 or 11 billion years ago is supposed to be largely metal free so the find here is *surprising*.]