What happened to the original rendering engine?

additionally at around after the first gleambow event that they changed the lighting software again to their own coded one which changed the glow of all gleam colors , especially shadow colors (my shadoooowwwww blueee sob) with that change darker gleam colors glowed less strong before all gleam colors had the same glow radius and strengh . also stuff got more “shiny” like marble

it should be this update