They said in one of the streams. We don’t know a lot of details, but we do know that:
The point of no return is longer than one hour
These tadpoles give special abilities, including psionic powers and immunity to sunlight for vampires, drow and presumably the ilithids spawned from them.
They will affect races normally immune to ceramorphosis, such as dwarfs and halflings, but that is old canon and could be a retcon to ceramorphosis in general.
