more alternatvies from discussion added

src/ipips/ipip-0431.md

@@ -196,7 +196,15 @@ Spend energy on creating CARv3 that solves the problems from "Motivation" sectio
 - native truncation detection and standardized error handling and passing during streaming
 - support for things like [Large Blocks](https://discuss.ipfs.tech/t/supporting-large-ipld-blocks/15093/)
 
-TODO: link to some public  artifact about CARv3
+TODO: link to some public artifact about CARv3
+
+#### Create a new multicodec for this metadata block
+
+Initially, we proposed to create a new multicodec for this metadata block called `car-metadata`. This was ruled out due to some concerns that you can find documented [here](https://github.com/multiformats/multicodec/pull/334#issuecomment-1668086641).
+
+#### Using CBOR instead of JSON for the metadata block
+
+We could use CBOR instead of JSON for the metadata block. However it was [decided](https://github.com/ipfs/specs/pull/431#issuecomment-1719634928) to opt for user readibility over number of bytes since CBOR doesn't greatly reduce the number of bytes in a key value map compared with JSON.
 
 ## Test fixtures