Thanks a lot, on step further. Found the json and .dll on my system and in the registry. Yet, when i try to configure anything in openXR via WMR or Devtools i get a promt, that the runtime app is not installed and a link to the MS Store (right), where my download fails. Thats the app i’m looking for.
Btw. MS-Support couldn’t help and recommended to download the app somewhere outside the store 