resolving merges on upgrade

I'm in the process of doing an upgrade from 11.4-RELEASE to 12.3-RELEASE.
I teed the output of upgrade to get a copy of the output:
   freebsd-update -r 12.3-RELEASE upgrade | tee /some-path/upgrade_11_4_to_12_3.log
At some point it complains that it can't merge some files in /etc,
and that it can't invoke vi because vi's stdin and stdout must be a terminal.
Then "do the changes look reasonable"

So... I said yes thinking I would look at them later before continuing.

Before doing a
   /usr/sbin/freebsd-update install
where can I find the newly accepted merged file so I can look at it?

I tried
   find / | grep etc/passwd
and only found the old version in /etc/passwd.

Thanks,

Gary