[ZIP 226]: Register ZIP 248 bundle type.

- Register OrchardZSA bundle type in the V6 bundle registry
- Update digest section to reference effects_bundles_digest and auth_bundles_digest
- Add reference to extensible transaction format ZIP
- Remove unused ZIP 244 and ZIP 246 references

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: nuttycom

zips/zip-0226.rst

@@ -83,6 +83,27 @@ Privacy Implications
 - When including new Assets we would like to maintain the amount and identifiers
   of Assets private, which is achieved with the design.
 
+Bundle Type Registration
+========================
+
+This ZIP registers the OrchardZSA bundle type in the V6 transaction bundle
+type registry defined in ZIP 248 [#zip-0248]_:
+
++------------+----------------------+--------------------+------------------+-------------+
+| BundleType | ``mValuePoolDeltas`` | ``mEffectBundles`` | ``mAuthBundles`` | Bundle kind |
++============+======================+====================+==================+=============+
+| TBD        |✅                    |✅                  |✅                | OrchardZSA  |
++------------+----------------------+--------------------+------------------+-------------+
+
+The OrchardZSA bundle has value pool deltas (transfers move value in and out of
+the transparent transaction value pool), effecting data (the OrchardZSA actions
+and burn information), and authorizing data (the proofs and binding signature).
+
+A transaction MUST NOT contain both an Orchard bundle (type 3) and an OrchardZSA
+bundle. The OrchardZSA bundle replaces the Orchard bundle for transactions that
+transfer Custom Assets.
+
+
 Specification
 =============
 
@@ -363,7 +384,7 @@ The transaction format for v6 transactions is described in ZIP 230 [#zip-0230]_.
 The ZSA-related changes in v6 include:
 
 * updates to the transaction structure [#zip-0230-transaction-format]_ and the
-  sighash digest computation [#zip-0246]_;
+  sighash digest computation [#zip-0248]_;
 * new note plaintext formats for both Sapling and Orchard outputs [#zip-0230-note-plaintexts]_,
   with corresponding changes to the note decryption algorithms for incoming and
   outgoing viewing keys [#zip-2005]_.
@@ -387,13 +408,18 @@ The following requirements on wallets are specified and motivated in ZIP 230
   temporarily inaccessible, until the wallet is upgraded to fully support v6 and to
   rescan outputs since v6 activation.
 
-Sighash modifications relative to ZIP 244 [#zip-0244]_
-------------------------------------------------------
+Modifications to Digest Algorithms
+----------------------------------
+
+The OrchardZSA bundle contributes to the transaction identifier and signature
+digest via the ``effects_bundles_digest`` and ``auth_bundles_digest`` defined
+in ZIP 248 [#zip-0248]_.
 
-Relative to the sighash algorithm defined in ZIP 244 [#zip-0244]_, the sighash algorithm
-that applies to v6 transactions differs by altering the Orchard bundle within
-the tree hash to match the corresponding OrchardZSA changes. See ZIP 246 [#zip-0246]_
-for details.
+The OrchardZSA bundle's value pool deltas (for both ZEC and Custom Assets) are
+committed via ``value_pool_deltas_digest``. The OrchardZSA effecting data
+(actions and burn information) is committed via ``effects_bundles_digest``.
+The OrchardZSA authorizing data (proofs and binding signature) is committed
+via ``auth_bundles_digest``.
 
 Transaction Fees
 ----------------
@@ -449,8 +475,7 @@ References
 .. [#zip-0230-note-plaintexts] `ZIP 230: Version 6 Transaction Format — Note Plaintexts <zip-0230.rst#note-plaintexts>`_
 .. [#zip-0230-orchard-note-plaintext] `ZIP 230: Version 6 Transaction Format — Orchard Note Plaintext <zip-0230.rst#orchard-note-plaintext>`_
 .. [#zip-0230-implications-for-wallets] `ZIP 230: Version 6 Transaction Format — Implications for Wallets <zip-0230.rst#implications-for-wallets>`_
-.. [#zip-0244] `ZIP 244: Transaction Identifier Non-Malleability <zip-0244.rst>`_
-.. [#zip-0246] `ZIP 246: Digests for the Version 6 Transaction Format <zip-0246.rst>`_
+.. [#zip-0248] `ZIP 248: Extensible Transaction Format <zip-0248.rst>`_
 .. [#zip-0307] `ZIP 307: Light Client Protocol for Payment Detection <zip-0307.rst>`_
 .. [#zip-2005] `ZIP 2005: Quantum Recoverability <zip-2005.md>`_
 .. [#protocol] `Zcash Protocol Specification, Version 2025.6.2 [NU6.1] or later. <protocol/protocol.pdf>`_