The RQ-180 does exist despite the numerous obtuse and outright denials from the USA over the years. In fact, only once before was it captured on film in California as it flew overhead.
This flying wing aircraft has been Top Secret for years created in the super secret Skunkworks located in Nevada. Not a lot of details have been revealed except for the fact it is a "high altitude flying reconnaissance" drone capable of traveling up to 14,000 miles at 60,000 feet, which allows it to go undetected in enemy air space to conduct surveillance missions on the ground with its extremely capable cameras that can read a license plate of a car. It is unarmed but thought to be extremely fast for a drone.
These drones have been deployed before in Guam and from there could easily fly over the Philippines, South China Sea and parts of China and back. This picture was taken on Sept. 2, 2021, and oddly enough, it is around the same time there was a joint naval task force with ships from several countries participating in naval exercises!
While it most likely the RQ-180 or its relative, it could be a Chinese Star Shadow, which has a very similar purpose and flying wing design. It is unknown if its operational but perhaps it is a test prototype. Another possibility is their Rainbow-7, which is also a flying wing design. The Star Shadow does have several prototypes in existence, so the chances that it is the one in the photo is a real possibility. Lastly, and the least likely, is that it was a Chinese H-20 Stealth Bomber, that has been secret for years. If it was, it would be just a test flight- but why fly over the Philippines?
Adding to the mystery of this is the fact the Philippine Airforce scrambled planes to intercept some unknown aircraft that did not respond to self identification. The interception was never within eyesight of the pilots but by the scrambled jets reached the area of the intruder, it was long gone. Again, was this the Chinese testing Philippine air defenses? Was it one of their drones?
Imagine, going out for a morning walk and looking up to see a flying wing!