The name of this map is mario_kart_deluxe_v3.
This is the Abstract Asylum end that shows the most notable part of it - the colorful Prism Prison. Souls inside it are unable to be freed and are composed of those that tried to gain power with Densopi`s sword just to destroy the Domains themselves and treasoned evil Leaders of Domains. They`re ot seen inside because they`re basially forgotten and only their essence is making the white light into colorful particles.
If a Suicide black-n-white soul passes the colors, it`ll gain its colors back with the song about love, the arch nemesis of Suicide Soldier, and will be free to abandon the Asylum.
TF2 -> Valve