The most common "DarkUI" is an addon that smooths and darkens the game's default textures. You can download the latest version as a zip from ESOUI .
There is a "Dark UI" mod for this sandbox game available on the Vintage Story Mod DB . Note that there is also a Dark UI 2 specifically updated for newer game versions. Download DarkUI zip
Most of these files come compressed and must be unzipped before use. The most common "DarkUI" is an addon that
Installing these usually involves more than just a download: Download DarkUI zip
For ESO , you typically move the extracted folder to Documents\Elder Scrolls Online\live\AddOns .