The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The whole zUI.lua is basically a copy paste of the pfUI.lua. Some obvious examples would be:
https://github.com/Ko0z/zUI/blob/master/zUI.lua#L27-L61
https://gitlab.com/shagu/pfUI/blob/master/pfUI.lua#L20-54
And if you scroll further, like the whole addon/module/namespace structure of pfUI and its functions has just been renamed. Same with the configuration UI, the tables.lua, the libraries (well at least you give a credit in one of them) and many of the components... The list is endless.
Seeing this without giving credit and not respecting the license at all makes me sad.