Question Ar Founation new pre release 5.0 version not visible in package manager !

For 2021.2 and 2021.3 you will need to manually update the AR Foundation entry in your Project manifest.json to access AR Foundation 5. This file can be found in your Project directory at Packages/manifest.json, where you can update the AR Foundation version number. You can find an example Project manifest entry in our Samples project: https://github.com/Unity-Technologies/arfoundation-samples/blob/main/Packages/manifest.json#L10