The following format specifiers are applicable to %DATEFORMAT%, %TIMEFORMAT%, and %DATETIMEFORMAT% meta-variables:
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c	Displays the date using the format given by the Operating System's ShortDateFormat, followed by the time using the format given by the OS LongTimeFormat. This is the default format used by IEHistory.
d	Displays the day as a number without a leading zero (1-31).
dd	Displays the day as a number with a leading zero (01-31).
ddd	Displays the day as an abbreviation (Sun-Sat) using the strings given by the ShortDayNames of the OS.
dddd	Displays the day as a full name (Sunday-Saturday) using the strings given by the OS LongDayNames.
ddddd	Displays the date using the format given by the ShortDateFormat OS variable.
dddddd	Displays the date using the format given by the LongDateFormat OS variable.
m	Displays the month as a number without a leading zero (1-12). If the m specifier immediately follows an h or hh specifier, the minute rather than the month is displayed.
mm	Displays the month as a number with a leading zero (01-12). If the mm specifier immediately follows an h or hh specifier, the minute rather than the month is displayed.
mmm	Displays the month as an abbreviation (Jan-Dec) using the strings given by the OS ShortMonthNames.
mmmm	Displays the month as a full name (January-December) using the OS LongMonthNames.
yy	Displays the year as a two-digit number (00-99).
yyyy	Displays the year as a four-digit number (0000-9999).
h	Displays the hour without a leading zero (0-23).
hh	Displays the hour with a leading zero (00-23).
n	Displays the minute without a leading zero (0-59).
nn	Displays the minute with a leading zero (00-59).
s	Displays the second without a leading zero (0-59).
ss	Displays the second with a leading zero (00-59).
t	Displays the time using the format given by the OS ShortTimeFormat.
tt	Displays the time using the format given by the OS LongTimeFormat.
am/pm	Uses the 12-hour clock for the preceding h or hh specifier, and displays 'am' for any hour before noon, and 'pm' for any hour after noon. The am/pm specifier can use lower, upper, or mixed case, and the result is displayed accordingly.
a/p	Uses the 12-hour clock for the preceding h or hh specifier, and displays 'a' for any hour before noon, and 'p' for any hour after noon. The a/p specifier can use lower, upper, or mixed case, and the result is displayed accordingly.
ampm	Uses the 12-hour clock for the preceding h or hh specifier, and displays the contents of the OS TimeAMString for any hour before noon, and the contents of the OS TimePMString for any hour after noon.
/	Displays the date separator character given by the OS DateSeparator.
:	Displays the time separator character given by the OS TimeSeparator.
'text'	Any text in single quotes is displayed AS IS.

Example: dd.mm.yyyy','hh:nn with say 20 Nov, 2003, 10:05:03 will tell IEHistory to show the date and the time as 
20.10.2003,10:05

The following format specifiers are applicable to %GROUPDATEFORMAT% meta-variable (CASE SENSITIVE!):
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d	Day of month as digits with no leading zero for single-digit days.
dd	Day of month as digits with leading zero for single-digit days.
ddd	Day of week as a three-letter abbreviation. The LOCALE_SABBREVDAYNAME OS variable associated with the locale is used.
dddd	Day of week as its full name. The LOCALE_SDAYNAME OS variable associated with the locale is used.
M	Month as digits with no leading zero for single-digit months.
MM	Month as digits with leading zero for single-digit months.
MMM	Month as a three-letter abbreviation. The LOCALE_SABBREVMONTHNAME OS variable associated with the locale is used.
MMMM	Month as its full name. The LOCALE_SMONTHNAME OS variable associated with the locale is used.
y	Year as last two digits, but with no leading zero for years less than 10.
yy	Year as last two digits, but with leading zero for years less than 10.
yyyy	Year represented by full four digits.