An exclusion clause is valid if it is clear and unambiguous, brought to the attention of the parties before or at the time of entering into the contract, and not contrary to public policy. Additionally, the clause must be reasonable and fair in the circumstances.

A term included in a contract that seeks to limit the liability of a party under the contract

Generally speaking the court would use the "4 corners doctrine" in interpretation of this clause. IE: that the exclusion itself, along with the whole of the agreement (contract) would define its limits (intentions).

Clause 231 was that Germany had to accept war guilt for starting the war.

War guilt clause