Reported by Valentun/Nova wallet.

To kill a pure proxy, we need to provide the block height at which pure proxy was originally created. Post AHM, this block height refers to the block height on Relay Chain network while the proxy pallet lives on the Asset Hub.

As Valentun describes it:

it becomes non-trivial to obtain block number from in the indexer to later be able to kill pure proxy

To improve the developer experience, we should extend the PureCreated Event to include the block height at which it was created. Optionally, we could also include the extrinsic index which is also required to kill pure proxy.