I suddenly felt I didn't get the behaviour from some scripts I had when running on Darwin/MacOS. Investigation showed that

$ fswatch . --event-flags

and then touching an existing file ´x´ gave the following output

/private/tmp/utman-test/x PlatformSpecific IsFile

I was expecting ... Updated isFile or something.

However touching a non-existing file gave the expected output

/private/tmp/utman-test/zz Created IsFile

I suppose the underlying fsevents or Darwin has changed somehow.

This happend (I think) after upgrading MacOS/Darwing to 10.15.4 (19E287).