Iβd this not based on how much of a planet is plotted? If a planet hit a plotted threshold it spawned a new one. Maybe I miss understood or was dreaming it.
Pretty sure this is just including the Sovs with visit rights set to public. I think Boundless Info and Boundlexx have the private worlds not shown due to a few Sov owner complaints early on in the Sov days.
Probably why we are at over 5000 planets βspawnedβ but the total number of planets visible on Boundlessxx and Boundless Info is 3216 or 3217 depending on which you are looking at.