Comment 11 for bug 910463

Another field that might be useful and could be easily added to this new 'System' pane:
Explicit full path to the preferences file, including the file name (see also bug #500961)

<off-topic>
A button to optionally reset the preferences (as mentioned in bug #500961) is a different (and AFAIU more complex) issue than simply displaying information, and probably would be best combined with a solution addressing requests which ask for other aspects of 'resetting the prefs' - see bug #784811 (reset only certain or broken settings) and bug #911700 (auto-recreate default prefs file in case of external mishap).
</off-topic>