When you are using Calendar Overlays you have the option of showing the title of the source Calendar that the Events in the Overlay came from. This option allows you to quickly identify which Events came from which Calendar. See the image below:
Depending on what colors are used in the events for your overlays (like event tags, overlay colors, and highlighting) it may sometimes be hard to see the overlay title text. The default color of the overlay title text is determined by your calendar theme. To change it, you'll need to create a custom theme for your calendar and then choose the color that works best.
To change the color of your overlay titles follow the steps in the image below:
See the image below for how changing the color of your overlay titles can improve your calendar's readability:
