Syntax: choose from drop down list
For refresh
-type walks, this controls how the Expires header is
used. Set to No
the Expires header will be ignored. Set to
Limited
the Expires header will be used, but limited by the
Minimum and Maximum Refresh Times. Set to Yes
the Expires header
will be treated as definitive.
Invalid and out of range headers will be ignored, with the exception of "0".