Johnson explains in diplomatic terms the Royal Proclamation (though he does not mention the formal document by name) at the end of the speech. Beginning is largely an appeal to trust the English now that they have won and disavow the French. End of speech essentially promising better conditions for them as long as they stop being enemies.

First day of congress

Niagara Congress Minutes, July 17, 1764. In “The papers of Sir William Johnson, Volume 11,” prepared for publication by the Division of Archives and History, pg 278-280. Albany: University of the State of New York, 1953. GKS ID: 58856.