Chronicle's project plan is actually a type of gantt chart. Wikipedia defines a Gantt Chart like this:
"A Gantt chart is a type of bar chart that illustrates a project schedule, named after its inventor, Henry Gantt (1861–1919), who designed such a chart around the years 1910–1915. Modern Gantt charts also show the dependency relationships between activities and current schedule status."
Chronicle does something similar by giving you a visual representation of the job using a bar for each activity based on the timing you selected in the Main System Setup. Chronicle also shows you the relationships of those activities based on the rules you setup in Main System Setup.
This is not connected to Chronicle's Scheduler in any way but you can, within the job file, move those bars around in case you need to extend the timing of activities to see how the job's timeline looks. Moving things from active to completed will also update the project plan.