The format is Netscape format as stated in the man page and this format is:
The layout of Netscape's cookies.txt file is such that each line
contains one name-value pair. An example cookies.txt file may have an
entry that looks like this:
.netscape.com TRUE / FALSE 946684799 NETSCAPE_ID 100103
Each line represents a single piece of stored information. A tab is
inserted between each of the fields.
From left-to-right, here is what each field represents:
domain - The domain that created AND that can read the variable.
flag - A TRUE/FALSE value indicating if all machines within a given domain can access the variable. This value is set automatically by the
browser, depending on the value you set for domain.
path - The path
within the domain that the variable is valid for.
secure - A
TRUE/FALSE value indicating if a secure connection with the domain is
needed to access the variable.
expiration - The UNIX time that the
variable will expire on. UNIX time is defined as the number of seconds
since Jan 1, 1970 00:00:00 GMT.
name - The name of the variable.
- The value of the variable.
(From "The Unofficial Cookie FAQ", edited for clarity)