The Ovrpulgins XML Manifest asks for READ_EXTERNAL_STORAGE. This causes a permissions check when the app starts (for photos / media / data, you know the scary one). I have no Idea how to fix it. I have tried overwriting the manifest, and editing the manifest. Unity just merges manifests and rewrites the permissions back in. I can't find the manifest it is merging in.
It is, but it sends that scary permissions check. (this check got my game rejected even through it is their check).the fix is to add this <meta-data android:name="unityplayer.SkipPermissionsDialog" android:value="true" /> to your manifest
if you are on OSX use "grep -rIin 'READ_EXTERNAL_STORAGE' ." might help you find the conflicting android manifest. run from the base of the project in terminal of course.
Looks like READ_EXTERNAL_STORAGE is only needed for some pre-Marshmallow OSes. Unfortunately, it is in Unity's current template AndroidManifest.xml, so you would have to hack it out in the staging area copy as described here: http://answers.unity3d.com/questions/1174614/modifying-androidmanifest-for-gearvr.html. Also be sure to build with API level 23 or higher.