@SNoiraud Very keen observation. So there’s a red herring here. The call stack in the defect appears to show the non-existent file:
C:\Program Files\GrampsAIO64-6.0.4\gramps\gen\filters\rules\event_matchespersonfilter.py
However, this is a consequence of the formatting changes in MantisBT (cc @Nick-Hall @lordemannd) which are mangling the actual filename (I ran into this before, but forgot!). If I edit the defect, I can see that the actual filename in the original data of the bug report is the correct file,
File "C:\Program Files\GrampsAIO64-6.0.4\gramps\gen\filters\rules\event\_matchespersonfilter.py", line 96, in apply_to_one
db.get_person_from_handle(family.father_handle)
So now that we have that out of the way, @daleathan I have confirmed that in my working installation of Gramps 6.0.4 and 6.0.3 on two different PCs do not contain the person event filter mentioned (note, the file is present in the file system). I used the search box as you suggested and Gramps presented no results.
The PC and the Windows sandbox clean installations I mentioned are all US English, and again neither Gramps 6.0.4 nor 6.0.3 have that filter. Could you confirm this in a sandbox/clean environment? Do you have any addon rules installed?