This concept slider LoRA was trained to correct the anatomy / quality issues with Klein models.

The LoRA can't fix everything but it helps. It was basically trained so that negative weights have the effect of a negative stable-diffusion prompt, and positive have the opposite effects.

Weight 2.0 mostly keeps the seed intact and can be used to fix minor glitches, 3.0 fixes some more prominent artifacts.

The LoRA also improves a bit the overall quality of the picture, makes the picture more "clean".