In more detail
Favourites are how you mark your strongest evidence while you refine. A starred quote rises to the top of its code in the reader, before the rest are ordered by illustrativeness, and Present mode features up to three favourites for each code.
Starring is a quick way to prepare for a supervision or a talk, and a useful prompt when choosing quotes for the write up.
In Themescape
Star quotes in Work mode, or mark them in the preferred column of the Data tab, where Y, Yes, TRUE, 1, x or a star all count. When you save your progress, the preferred column is set to your current stars.