EndArrayPlugin is an internal plugin, It is automatically included in GSAP's core and doesn't have to be loaded using gsap.registerPlugin().
You can think of internal plugins as just a part of GSAP.
The endArray plugin enables you to tween an Array of numeric values to a different Array of numeric values with easing applied.
const arr = [1, 2, 3];
endArray: [5, 6, 7],
If you have Arrays of uneven lengths, only the indexes that are in both Arrays will be animated.