We know it is above zero, because they agreed to set tariff free trade as a target for the negotiations, which they'd ordinarily never do in an FTA.
We can infer this from common sense, economics, the EU's behavior during the Withdrawal Agreement negotiations, and the EU's recent statements.
Are businesses telling them to preserve tariff free trade at all costs?
Are national capitals engaged on this issue, relaxed about it?
Much will depend on the value, internally, that the EU places on salvaging individual components.