What they want is a new field on the module settings form, where you can enter an estimated time required to complete that activity/read that resource. This would be an extra setting in the 'Common module settings' section of the form. It would, of course, be perfectly acceptable to leave that blank.
Then on the course home page, for any activity that has time required set, this is listed by the corresponding activity. The idea is that this makes it easier for students to plan their work.
To implement this, I think I need to
- add an int timerequired column to the mdl_course_modules table that stores the time in seconds.
- add another form field to the 'Common module settings' to let people set this. I am thinking of a dropdown with the options Not set, 5 mins, 10 mins, 15 mins, 30 mins, 45 mins, 1 hr, 1 1/2 hrs, 2 hrs, 3 hrs, ... 10 hrs.
- Display this next to activities on the course home page in all course formats. I think that just means editing print_section from course/lib.php. Obviously this information needs to be displayed surrounded by an appropriate <span> tag so themers can style it as they wish - and I need to make it look nice in the standard theme.