the engine wa first created as paradox by the company Silicon Studios (they worked on some games and some middle ware for post effects for other renderers)

Then it has been renamed as xenko for some reason.

Once it has been open sourced in 2018, we wanted to make it part of the .NET foundation but we didn't have the trademark rights for it. Or more like, Silicon Studios was taking a lot of time answering to give us the trademark. We voted to change the name and allowing us to be part of the foundation.