.ckpt (PyTorch Checkpoint), which is the standard format used by early versions of Stable Diffusion (v1.4/v1.5) for distributing model weights.
It is part of the WD-F99 project by developer dimaskool . Key Characteristics f99.ckpt
As a .ckpt file, it is designed for use in interfaces such as Automatic1111's Stable Diffusion WebUI or ComfyUI . Technical Note .ckpt (PyTorch Checkpoint)
The "WD" in the name suggests it is a version of Waifu Diffusion , a popular open-source model trained on the Danbooru dataset to improve anime character rendering and tag comprehension. f99.ckpt
Models like this are typically optimized to handle specific aesthetic tags and intricate details common in modern anime art styles that base models often struggle with.