Firefox and Chrome preference reading attempt

When starting the debug mode in Hazel and going through the log file, I came across the following:
Why is Hazel attempting to read browser preference files? I don't have any rules set for these directories.
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2021-05-23 13:12:02.711 hazelworker[61607] DEBUG: Program is licensed.
2021-05-23 13:12:02.726 hazelworker[61607] DEBUG: Error reading file /Users/myusername/Library/Application Support/Firefox/prefs.js: Error Domain=NSCocoaErrorDomain Code=260 "The file “prefs.js” couldn’t be opened because there is no such file." UserInfo={NSFilePath=/Users/myusername/Library/Application Support/Firefox/prefs.js, NSUnderlyingError=0x7fb0aa019120 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}
2021-05-23 13:12:02.728 hazelworker[61607] DEBUG: Could not find entry for default_directory in Chrome preference file.
Why is Hazel attempting to read browser preference files? I don't have any rules set for these directories.