How to show the host/configured/default ssh "configuration"?
There is -G option in recent openssh, which behaves in similar way as -T on server side.
-G Causes ssh to print its configuration after evaluating Host and Match blocks and exit.
By calling ssh -G host you will get options used for connecting to specific host, which can be helpful for debugging conditional matches in ssh_config.
Also setting more verbose log level (-vvv) can help with debugging config parser.