One of not-so-lovely features of taglog is that time is displayed with a precision to a second. Personally, I doubt it's always required. However, I do agree that some users may find it crucial.
Hence, for those who don't care about seconds in time logging, the patch may come up handy.
The patch basically adds new preference - Time Format - to specify printf-style format line (as far as I can tell, it's the same for the format function in Tcl/Tk) for time display. There are currently two provided values: default (with seconds), no seconds (without seconds). The entered string is used to format three numbers - hours, minutes, seconds.
And the preference is used everywhere, where I could find, to format time for display purposes.
There is also basic help in English.
Time Format preferences