org-time-clocksum-format

org-time-clocksum-format is a variable defined in `org.el'.
Its value is

(:days "%dd " :hours "%d" :require-hours t :minutes ":%02d" :require-minutes t)

Documentation:
The format string used when creating CLOCKSUM lines.
This is also used when Org mode generates a time duration.

The value can be a single format string containing two
%-sequences, which will be filled with the number of hours and
minutes in that order.

Alternatively, the value can be a plist associating any of the
keys :years, :months, :weeks, :days, :hours or :minutes with
format strings. The time duration is formatted using only the
time components that are needed and concatenating the results.
If a time unit in absent, it falls back to the next smallest
unit.

The keys :require-years, :require-months, :require-days,
:require-weeks, :require-hours, :require-minutes are also
meaningful. A non-nil value for these keys indicates that the
corresponding time component should always be included, even if
its value is 0.


For example,

(:days "%dd" :hours "%d" :require-hours t :minutes ":%02d"
:require-minutes t)

means durations longer than a day will be expressed in days,
hours and minutes, and durations less than a day will always be
expressed in hours and minutes (even for durations less than an
hour).

The value

(:days "%dd" :minutes "%dm")

means durations longer than a day will be expressed in days and
minutes, and durations less than a day will be expressed entirely
in minutes (even for durations longer than an hour).

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.