Whatever the hell it is, the Great Pyramid was a lousy undecorated and unnamed tomb, unlike most Egyptian tombs. Not even a naming hieroglyph on the “sarcophagus” after all that work. Bah!
I’m glad that the Egyptologists assumptions are finally being questioned.
The wall paintings finished crumbling off just in the past 150 years or so -- one of the old time Egyptologists found and recorded what was left of an inscription, which made reference to such-and-such a year of the cattle drive. The moisture in the GP is quite high, the Egyptians (who don't want to allow some kind of destructive drilling) jackhammered in a ventilation system about 20 years ago to try to keep it dried out, given the addition of tourists' breath and sweat.
During classical times the Great Pyramid was open to tourists, and the real entrance (not the chiseled-out thieves' hole chipped by order of the caliph during the Dark Ages) made it possible to visit some of the currently unknown (and officially denied) passages, going right up to the rear exit of the King's Chamber. At that time there was still a pile of grave goods in the adjacent room (again, currently unknown), and a traveller of classical times wrote about it. During Byzantine times the Pyramid was resealed (probably an idolatry thing). I suspect the caliph snagged the riches, and if not, the late Romans or the Byzantines did it.