Usually we will open the debug mode to trace the connection and locate the problem. When the server side is disconnect, client side will get a message "debug1: Exit status -1". Some non-experienced users will be misled by this message and think that the issue resides on the client side. Whether we can add an addition message for explaining the exit status is from which side? Such as "debug1: Exit status 1 from remote server hostname.xyz".
I think the existing debug message is accurate because it literally shows what the client will exit with. The next line after that debug message is exit(exit_status) :) Moreover, this value will not always be derived from the server - there a number of cases where it's possible for the value to come from the client alone: ssh -N and a server that doesn't send the channel exit-status message (which is optional in the protocol) are two that come to mind.
closing bugs resolved before openssh-8.9