And why would anyone, even fucking loon Aerys, store wildfyre under a fucking dragon pit??
Mad King Aerys did store caches of wildfire around KL in the books. Locations included the Great Sept of Baelor, Red Keep and ....... The Dragonpit.
The dragons had all died out at least a hundred years earlier, so no danger of dragon fire there!
Bran's vision of a dragon over KL in season 6 followed by a wildfire explosion could foreshadow this.
It sounds like fanfic, but I am casting my mind back to a thought I had last year....
'Jon, Jorah, Gendry, Beric, Tormund, Thoros and he Hound go north of the wall to catch a Wight to prove they exist...... That sounds like pure fanfic'.