We're trying to get this upstreamed so I actually expect PlayCanvas to talk about it in the future. Here's the reference (cpu) decoder: https://github.com/vincentwoo/blog/blob/master/3d/sutro_towe..., as well as a gpu one: https://github.com/vincentwoo/blog/blob/master/3d/sutro_towe....

For more information on the format itself you can look at https://github.com/nerfstudio-project/gsplat/blob/main/gspla....