these 2 derivations will be built:
  /nix/store/7vvz91hjmz5j3cnsrrxhagvjciwpbvxq-realistic_rendering_demo.zip.drv
  /nix/store/nxkq9lq5kqyrk44ac5xv238krc6c9m4a-ue4demos-realistic_rendering.drv
building '/nix/store/w82b5qnxp10awxwyh071497myj4mawba-realistic_rendering_demo.zip.drv'
realistic_rendering_demo.zip> 
realistic_rendering_demo.zip> trying https://ludios.org/mirror/ue4demos/realistic_rendering_demo.zip
realistic_rendering_demo.zip>   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
realistic_rendering_demo.zip>                                  Dload  Upload   Total   Spent    Left  Speed
realistic_rendering_demo.zip> 100  201M  100  201M    0     0  21.1M      0  0:00:09  0:00:09 --:--:-- 20.0M
building '/nix/store/nxkq9lq5kqyrk44ac5xv238krc6c9m4a-ue4demos-realistic_rendering.drv'
ue4demos-realistic_rendering> Archive:  /nix/store/iavi4nxjb5i113najwxd3f705g7fw764-realistic_rendering_demo.zip
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/Engine/
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/Engine/Binaries/
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/Engine/Binaries/Linux/
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/RealisticRendering  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libicudata.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libicui18n.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libicuio.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libicule.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libiculx.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libicutu.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libicuuc.so  
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/Engine/Binaries/Linux/libopenal.so.1  
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/RealisticRendering/
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/RealisticRendering/Content/
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/RealisticRendering/Content/Paks/
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/RealisticRendering/Content/Paks/RealisticRendering-LinuxNoEditor.pak  
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/RealisticRendering/Saved/
ue4demos-realistic_rendering>    creating: Realistic Rendering Demo/RealisticRendering/Saved/Config/
ue4demos-realistic_rendering>   inflating: Realistic Rendering Demo/RealisticRendering/Saved/Config/controller.vdf  
ue4demos-realistic_rendering>  extracting: Realistic Rendering Demo/RealisticRendering/realisticrendering.png  
ue4demos-realistic_rendering> Realistic Rendering Demo

upload niks3: ok