FeeStrategy::AbsoluteFee was implemented by smuggling the fee into value_sum and setting the feerate to zero. This meant the coin selector had no awareness of the fee, which interacted poorly with RBF logic (the zero feerate bypasses the original tx's feerate floor). Removed in favor of a direct target_feerate: FeeRate field.
Originally posted by @evanlinjin #39 (comment)
Originally posted by @evanlinjin #39 (comment)