I don't know what this thing is supposed to exactly, but keep in mind that DXVK does not hook anything and instead completely replaces the respective DLLs, and therefore has to sit at the bottom of the stack.

We're not doing anything that would prevent external mods from working either, as long as they don't rely on weird features we don't support or interact with the wrong DLLs.

it's a dll loader. it has a dll that you must rename to a specific name in order for a game to load it. once it is loaded, you can put a dll in the plugins folder or change the .dll to .asi and put in the plugins folder and it will load everything you put in that folder. For example, I can keep the reshade64.dll and change the name to reshade64.asi and put it in UAL plugin folder and it runs with no problem.

But, a specific game example, if you put dxvk along side the UAL dll(in this instance for this game, UAL dll should be named winmm.dll) (both in main directory of lets say, Eiyuden Chronicles where you need to use both the dxgi.dll and the d3d11.dll of dxvk for this game) it works and an indication of it working would be the 2 log files that dxvk makes. But, if you put dxvk inside the UAL plugin folder, the game doesnt load it (indicated by the dxvk log files not showing up).