This upscaler is not mine, all the credit goes to: XINNTAO

Official WIKI page: openmodeldb

License of use it: BSD-3-Clause

HOW TO INSTALL:

Rename the file from: realesrganX4plusAnime_v1.pt to RealESRGAN_x4plus_anime_6B.pth

Copy the file RealESRGAN_x4plus_anime_6B.pth inside the folder: stable-diffusion/models/RealESRGAN

Restart/Reload you Stable Diffusion instance

The upscaler should be visible for hi-res and extras tabs