The Cathedral Concept
These mushrooms were created from the vanilla textures using trained artificially-intelligent upscale-models. They also had some manual quality adjustments such as restoring vanilla colors with an overlay to reduce color-noise.
Regarding compatibility, these textures use the vanilla mushroom normal maps, so if you have mushroom normal maps from other mods that you are overwriting with Cathedral, you'll want to disable them.
There are two primary philosophies when it comes to modding, Parlor and Cathedral, originally coined by the former modder, Wrye.