You need to create it for yourself. Create a new String in your Preferences called
ChatLogTimeStampFormat and give it a value of
HH':'mm':'ss for 24 hour clock or
hh':mm':'ss tt for 12 hour clock with AM or PM.
.
More info on these values-
Date Tags
To add normal text, use single quotes. Example: "dd'/'MM" will produce "18/10".
- 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.
- dddd - Day of week as its full name.
- 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.
- MMMM - Month as its full name.
- yy - Year as last two digits, but with leading zero for years less than 10.
- yyyy - Year represented by full four digits.
Time Tags
To add normal text, use single quotes. Example: "HH':'mm" will produce "12:40".
- h - Hours with no leading zero for single-digit hours; 12-hour clock.
- hh - Hours with leading zero for single-digit hours; 12-hour clock.
- H - Hours with no leading zero for single-digit hours; 24-hour clock.
- HH - Hours with leading zero for single-digit hours; 24-hour clock.
- m - Minutes with no leading zero for single-digit minutes.
- mm - Minutes with leading zero for single-digit minutes.
- s - Seconds with no leading zero for single-digit seconds.
- ss - Seconds with leading zero for single-digit seconds.
- t - One character time-marker string, such as A or P.
- tt - Multicharacter time-marker string, such as AM or PM.