This is a port of ClearDespawn to a new mod loader Fabric.
Clear Despawn is a mod that makes dropped items flash when they're about to despawn. By default, this happens when the item has about 20 seconds left until despawn and the flashing gradually gets faster as the timer goes down. Both of these elements have configuration options.
This mod is client-side only.
There's not much else to say, so here's an example gif: