Been manually adding it in every new project for the past year, hoping it was just a forgotten feature which would eventually be implemented, but now we're getting impatient. Its impossible to develop extensions (in other packages) without the ability to reference it.
I have started working on an actual "Unity Package" that just turns the Oculus integration into a proper UPM package. Let me know if you'd be interested in trying that out, not sure if the current terms allow publicly sharing it.
