I came across this plugin on Godot Asset Store: https://godotassetstore.org/assets/tools/3d/gh:OfficinePixel:vr_mobile_camera
I was looking for a way to run Godot VR applications on low-cost Android phone that does not have a gyroscope. So the above plugin looks like a solution. But when I search for this plugin on Godot Asset Library (using the Godot IDE), I did not find it. Is the asset store different from asset library?
Yes, that's something different from some third party. If you scroll down on that linked page you see it says it's by Ten-ton Creations. I'm not familiar enough so I can't comment on their rep.