"Broken RAW" warning: questions

First time user here, so maybe I am just missing it. (Also couldn't find an easy way to search the forum here beyond Google, so forgive me if this has been discussed already.) Where does the warning appear when FRV encounters a corrupted file? I have the "warn on broken RAWs" option checked, and I am not seeing anything when I browse to a few known-corrupted files. I thought it would be an obvious warning (like a dialog box that pops up), but I am not seeing that or anything in any of the status bars or panes.
 
I tested it on two of my own RAW files which had big blocks of binary zeroes inserted during a bad copy process, and also the sample files posted at https://www.fastrawviewer.com/blog/dealing-with-damaged-raw-files
None of them seem to generate a warning.
 
A second related question is: What kind of corruption can FRV detect? Obviously there might be some types of errors that could go unnoticed. But when I processed my own two corrupt samples with dcraw, I got a "Corrupt data near 0x______" type warning. Figuring that FRV is at least somewhat related to the dcraw concepts/code, I would have expected to see a warning on these particular files.
 
Not a deal-breaker as this seems like a very useful program, but any insights would be appreciated.