Looking at your second answer first, I tried the "gsettings list-recursively ..." but it didn't give any output. That might be because I'd previously fixed the file to be world-readable after I'd noticed the messages in the journal.
I've tried turning off world-readability but the messages haven't reappeared. Seems like whatever was trying to access the file has been satisfied when I let it read the file.
Looking at your second answer first, I tried the "gsettings list-recursively ..." but it didn't give any output. That might be because I'd previously fixed the file to be world-readable after I'd noticed the messages in the journal.
I've tried turning off world-readability but the messages haven't reappeared. Seems like whatever was trying to access the file has been satisfied when I let it read the file.