Keystone: Flynn.
What is the purpose of a keystone? An arch? A bridge? A bridge is to cross something.
Maybe all the hoopla in the media over the last year or so have been a bridge to get us to the promise land, the post-cabal land. Keystone is that stone connecting the supporting stones, the stone that keeps the arch together.
Past drops with 'Bridge'
There's more than these screencaps, but these are the ones I thought interesting pertaining to 'keystone' concept.