ACNet is the abbreviation of Anime4KCPP Net, designed for high-performance anime style image and video upscaling, so it has nothing to do with Asymmetric Convolution Net, although they have the same abbreviation. ACNet is Anime4KCPP own CNN based algorithm.

ACNet use less convolutions per layer (Up to 8) but more layers to get less parameters while ensuring quality.
Waifu2x's Upconv_7 has 552,480 parameters total, and 7 layers.
ACNet has 4,784‬ parameters total, and 10 layers.

In VapourSynth plugin of Anime4KCPP with ACNet on