org-columns-modify-value-for-display-function

org-columns-modify-value-for-display-function is a variable defined in `org.el'.
Its value is

nil

• This variable may be risky if used as a file-local variable.

Documentation:
Function that modifies values for display in column view.
For example, it can be used to cut out a certain part from a time stamp.
The function must take 2 arguments:

column-title The title of the column (*not* the property name)
value The value that should be modified.

The function should return the value that should be displayed,
or nil if the normal value should be used.

You can customize this variable.