This feature was exclusively part of a joke version and is not currently planned for addition to regular Minecraft. It is documented here on the wiki due to being officially-released content by Mojang Studios, even if not present in a final version.
Biome For Player With No Time For Nonsense is a joke biome introduced in Java Edition 20w14∞. It generates in the "busy" dimension.
The biome seems like a normal snowy taiga, although mineral blocks and redstone components generate instead of ores. Unlike in normal snowy taigas, no igloos or mobs spawn here.