Adding a logo url field to the token metadata api

cip-0056/cip-0056.md

@@ -202,7 +202,7 @@ explained in [Canton Coin Limitations](#canton-coin-limitations).
 The standard defines six APIs. Each consists of an on-ledger Daml API and
 optionally an off-ledger HTTP API. The six APIs and their purpose are:
 
-- *token metadata API*: serve symbol name, total supply, URL for registry-specific UI, other metadata
+- *token metadata API*: serve symbol name, total supply, URL for registry-specific UI, URL for a token logo or image, other metadata
 - *holdings API*: populate portfolio view and transaction history
 - *transfer instruction API*: initiate and monitor FOP transfers
 - *allocation API*: allocate assets to execute DVP transfers
@@ -336,8 +336,8 @@ usefulness.
 
 The metadata keys defined by this CIP are defined as part of
 [splice](https://github.com/hyperledger-labs/splice) and thus prefixed with
-`splice.lfdecentralizedtrust.org/`. Concretely, this CIP introduces the following two
-metadata keys:
+`splice.lfdecentralizedtrust.org/`. Concretely, this CIP introduces the following three
+optional metadata keys:
 
 - `splice.lfdecentralizedtrust.org/registry-urls`: a comma-separated list of URLs of
   the off-ledger APIs of a registry, used to [discover the off-ledger APIs of registries](#off-ledger-api-discovery-and-access)
@@ -349,7 +349,6 @@ metadata keys:
   from the default path (e.g., withdrawing an allocation or aborting a transfer
   instruction).
 
-
 ##### Metadata Key Syntax
 
 Metadata keys follow the same format as [Kubernetes Annotations](https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/),
@@ -408,6 +407,13 @@ Registries may optionally report the total supply of a tokenized asset on the of
 If they decide to do so, then that total supply should be computed by summing up the `amount` field of
 all active  `Holding` contracts with a matching `instrumentId`.
 
+##### Logo URL
+
+Asset issuers could optionally include a public URL to the logo image associated with the token on the 
+off-ledger token metadata API. The logo image of the token can be used in for display in exchanges, wallets
+and user interfaces. It's recommended that the image should be a 200x200 pixels in size, in PNG, JPEG, 
+or WEBP format with a transparent background.
+
 
 ## Motivation
 
@@ -572,6 +578,7 @@ This CIP is licensed under CC0-1.0: [Creative Commons CC0 1.0 Universal](https:/
 
 * **2025-03-18:** - Initial Draft
 * **2025-03-31:** Approval announced via [mailing list thread](https://lists.sync.global/g/cip-announce/topic/cip_0056_canton_network/112004244)
+* **2025-11-25:** - Addition of the Logo URL optional field in the off-ledger token metadata API ([draft PR](https://github.com/hyperledger-labs/splice/pull/3210))
 * **2025-12-01:** Replaced implementation proposal section with references to the actual implementation
   that was released as part of [Splice 0.4.0](https://docs.dev.sync.global/release_notes.html#id-0-4-0).
 * **2025-12-03:** Updated Canton Coin limitations to reflect the state as of Splice 0.4.23.