Most of the Xaya platform (in particular, libxayagame) is blockchain agnostic and needs only very basic functionality of the underlying base chain. Traditionally, the base chain for Xaya applications has been Xaya Core, but it is possible to run Xaya GSPs with other base chains as well to expand the reach of the Xaya platform.
Xaya X provides the tools to run an interface layer based on another blockchain, but which exposes a Xaya-Core-like interface so that GSPs built with libxayagame can run out-of-the-box on that base chain.