Their could be more than one meaning to
Keystone.
The Keystone is the top piece of the Royal Arch in Masonry.
We connected Masonry both to the Queen and to the False Flags, which are being used to condition the society/ public
The Vatican is laid out like a key.
pic related.
Geomancy?
don't believe in it?
Check out
"Secrets in Plain Sight" if you haven't seen it.
? https://www.youtube.com/watch?v=L777RhL_Fz4
(And if you have seen it, perhaps review it? I certainly need to)
The powerful overloard occultists lay out land , building structures an roads sometimes at important locations, in specific coded ways.
Maybe that's why the "Keystone" found by the Plane fags near D.C.? means something.
Haven't had a chance yet to study it
The Royal Arch of the Masons is connected to Solomon's Temple. Therefore: Solomon's key?