When items are about to despawn, they flash to let you know that you might want to pick them up before it's too late. Everything is configurable, from the flashing speed to the shadow opacity.
You can get to the settings via Mod Menu, but also by setting a keybind (it's unassigned by default).
This is a rework of the ClearDespawn mod for Fabric 1.21.x. I might add support for more loaders later.
External resources
Project members
Thijzert
Owner
Technical information
License
MIT
Client side
required
Server side
unsupported
Project ID