ostree-admin-config-diff man page
ostree-admin-config-diff — Diff current /etc configuration versus default
ostree admin config-diff [Options...]
Prints the differences between the current /etc directory and the default configuration in /usr/etc. Newly added files (present in /etc but not in /usr/etc) will be prefixed with 'A'. Modified files will be prefixed with 'M', and deleted files with 'D'.
Use a different operating system root than the current one.
$ ostree admin config-diff
M shadow A example.txt