Merely launching Safari and turning on JavaScript (and cookies) produces a pack of files, all with the extended attribute 'com.apple.quarantine'.
This is before any surfing is done.
Xscan is set to search specifically for files with extended attributes and it comes up with them all.
XaBatch opens a customised batch file for dealing with these files (and others). XaBatch then scours all user files for signs of 'com.apple.quarantine' (and other extended attributes) and cleans them out.
Nearly 6,000 user files are cleaned of a dozen extended attributes in a matter of seconds. All done!