FAA Order 8130.34D — UAS Operating Limitation A-30
Appendix A · p. A-7
When filing a flight plan, the experimental nature of this UA must be listed in the remarks section. The pilot will notify the control tower of the experimental nature of the UA when operating the UA into or out of airports with operating control towers.
This limitation is only required for programs where a flight plan is required and transitions are permitted at airfields with a control tower. Reference the FAA Form 7711-1 to verify these requirements. Due to equipment and operational constraints of some UAS, this limitation will not always be required.
Verify it yourself: the eyeball above opens the exact page of Order 8130.34D with this limitation highlighted.