Document shared to per-spend anchor conversion
@@ -323,6 +323,9 @@ impl Transaction {
/// returning `Spend<PerSpendAnchor>` regardless of the underlying
/// transaction version.
///
+ /// Shared anchors in V5 transactions are copied into each sapling spend.
+ /// This allows the same code to validate spends from V4 and V5 transactions.
+ ///
/// # Correctness
///
/// Do not use this function for serialization.
