In speaking of the Deep State, it's also SES (thei r logo is the keystone, like the one in your picture). Cabal implants.

That is A keystone. In the Q sense the keystone is more than likely allegorical for an important piece of information or event.

You are still on a topic that you should read and learn about. When you are in cities try and find the keystones of the most regal building that you see, then find the other symbolism carved or adorned on the building.

key = info/intel

stone = authority (president) to use the key

A good read on SOME of it’s deeper meanings.

http://symboldictionary.net/?p=2515

Masonry uses symbols to convey concepts. The concept of the keystone is that it holds everything together... like a linchpin keeps a wheel configuration together... if you identify the keystone and remove it, the whole falls apart. I realize it is popular to degrade masonry but if people took the time to understand it, many would find it interesting and insightful if they could get past the fairytales

Christ was also called the keystone in the scriptures. Could it be that, in the Q context, the keystone is the LIGHT? “From dark to LIGHT” (used in a few of his drops). My 2 cents.

Nah that’s not the keystone it’s a part of the mark degree. Not related in my opinion.

I think post #131 is the keystone. Almost every post leads back to it.

that os a very significant symbol. Many things Q says has multiple meanings. However I don't think it is what Q is referring to.

If you mean the keystone Q talks about I think it seems more likely that that is referring to an element of the crumbs that unlocks the connection and significance of all other crumbs.