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-sd-91a59431a6dd, and instructions/examples at https://github.com/enryu43/anifusion2-stable-diffusion.
Also, the original checkpoint in the Latent Diffusion format is available.
Installation instructions for webui: https://gist.github.com/enryu43/fccaa7f165ffcb214780d203c565761f