Each button in this panel shows the name of a module which has alternates available.
So, "lectionay day" would indicate that there are other occasions that could be celebrated on this date.
"titles" would indicate that there are other titles that could be used for this occasion.
"readings" would indicate that there is one or more alternate readings for this occasion.
Clicking on a button opens a screen that shows the available alternates for the selected module, and allows the selection of diffferent alternates.
The "Help" button, shows this screen.
The "Done" button, closes the screen.