Most of the visible content in a Deki scene comes from this package. It ships the day-to-day 2D components an interactive 2D project needs: sprites, text rendering with BitmapFont and live TTF baking in the editor, sprite-sheet animations, procedural gradients, buttons with pressed / hover states, scrollable containers, clip regions, and picker-wheel rollers.
Every component it adds, every exported property and its changelog are in the deki-2d reference.