#1477 do not remove comments refering TransactionBuilder, but instead mention that TransactionBuilder was removed

ts_src/psbt.ts

@@ -117,6 +117,8 @@ export class Psbt {
       __NON_WITNESS_UTXO_BUF_CACHE: [],
       __TX_IN_CACHE: {},
       __TX: (this.data.globalMap.unsignedTx as PsbtTransaction).tx,
+      // Psbt's predecesor (TransactionBuilder - now removed) behavior
+      // was to not confirm input values  before signing.
       // Even though we highly encourage people to get
       // the full parent transaction to verify values, the ability to
       // sign non-segwit inputs without the full transaction was often
@@ -1294,7 +1296,8 @@ function getHashForSig(
       console.warn(
         'Warning: Signing non-segwit inputs without the full parent transaction ' +
           'means there is a chance that a miner could feed you incorrect information ' +
-          'to trick you into paying large fees. You are not ' +
+          'to trick you into paying large fees. This behavior is the same as Psbt\'s predecesor ' +
+          '(TransactionBuilder - now removed) when signing non-segwit scripts. You are not ' +
           'able to export this Psbt with toBuffer|toBase64|toHex since it is not ' +
           'BIP174 compliant.\n*********************\nPROCEED WITH CAUTION!\n' +
           '*********************',