This model is converted with https://github.com/huggingface/diffusers/blob/main/scripts/convert_original_stable_diffusion_to_diffusers.py.
However, the tokenizer in the diffuser model is wrong, for proper usage, see description at https://medium.com/@enryu9000/anifusion-diffusion-models-for-anime-pictures-138cf1af2cbe, and instructions/examples at https://github.com/enryu43/anifusion-stable-diffusion.
Also, the original checkpoint in the Latent Diffusion format is available.
Installation instructions for webui: https://gist.github.com/enryu43/858999bf69dc92b97fdad6137c3c45e6