How does a user use an Android device? They usually interact with the user interface. Ideally, they should be comfortable using that interface and a major factor in that comfort is how elements are sized. With Android 13 Developer Preview 2, the OS is looking to make it just a bit easier to do by killing two birds with one stone.
Specifically, users can toggle font size (affecting all text you see in and out of apps) and something called "Display size" which controls other parts of the visual layout such as buttons, dialog boxes, and pictures.
Currently on Android, you'll find font size and display size as separate menu items in the system display settings. DP2, however, wrangles them into a single item called "Display size and text," leading to an example home screen illustrating different font and icon size options. In addition to toggling on high contrast mode for text, as 9to5Google points out, users would get a new switch to have bold text in UI.
In all, a sensible bit of streamlining we wouldn't mind seeing arried over to the stable release. Keep track of Android 13 developments with Android Police.