Effective February 25, new regulations have been posted in the Federal Register pertaining ID markings for drones. An FAA-issued registration number will be required to be displayed on an outside surface.
There is no requirement of a specific location on the external surface for the ID to be placed. The registration number must be easily located on the exterior.
Previously, there was some flexibility afforded in the location of the registration. Originally, the FAA required that the ID be readily accessible and readable. In turn, some drone operators were able to place registrations in an enclosed compartment like a battery case, as long as it was accessible without tools.
The new rule is in response to a concern about risks for first responders. Concealed explosive devices on a drone could pose a risk when they open a compartment to find the registration number. Now, first responders no longer have to directly handle the drone to view identification.