The left panel depicts the planet radius-orbital period plane, containing all the transiting planets with sizes <4 R_⊕ orbiting low-mass stars (stellar mass <0.70 M_⊙). The green contours represent the density distribution of all of these planets. The gray dots are planets with density estimations better than 30%. The dashed line refers to the prediction using thermally driven mass-loss mechanisms, such as photoevapora-tion and core-powered mass-loss. On the other hand, the solid line represents the prediction from the gas-poor formation model. Planets inside the region limited by these two lines are referred to as ‘keystone’ planets. The red and the blue dots refer to the planets TOI-2096 b and c, respectively. The right panel displays the radius frequency, showing the radius valley and the location of planets b (red band) and c (blue band) encompassing it.