Does it use file attributes (modified time, filesize, etc.) or does it use a hash value and check hashes… or both?
I’d personally prefer if it just used file attributes, that way changes due to bit rot or other corruption that doesn’t change the file attributes wouldn’t propagate.
Definitely attributes - imagine you’d have to rehash all the data every minute (default before watching was present). Thus unless there is also a change in attributes, in which case the file is rehashed, bit rot or other corruption wont be picked up.