# Use the xattr command. You can inspect the extended attributes:
$ xattr s.7z
com.apple.metadata:kMDItemWhereFroms
com.apple.quarantine
# and use the -d option to delete one extended attribute:
$ xattr -d com.apple.quarantine s.7z
$ xattr s.7z
com.apple.metadata:kMDItemWhereFroms
# you can also use the -c option to remove all extended attributes:
$ xattr -c s.7z
$ xattr s.7z
# xattr -h will show you the command line options, and xattr has a man page.
