Based on @krofax 's comments

Author: qbzzt

pages/stack/interop/superchain-weth.mdx

@@ -72,7 +72,7 @@ sequenceDiagram
 #### Initiating message
 
 1.  The user (or a contract operating on a user's behalf) calls `SuperchainWETH.sendETH` with a destination address and a chainId.
-    This call should have an attached amount of ETH.
+    ETH, in the amount to transfer must be attached to this call.
 
 2.  `SuperchainWETH` transfers the specified ETH amount to `ETHLiquidity`, removing it from circulation on the source chain.