Target

A target is a block that provides a temporary redstone charge when hit by a projectile.

Obtaining
Targets can be mined using any tool or by hand, but a hoe is the fastest way to break it.

Usage
Targets emit a redstone signal when hit by most projectiles. This includes arrows, tridents, eggs, snowballs, splash potions, fire charges fired by a dispenser, lingering potions, bottles o' enchanting, ender pearls, and llama spit. The closer a projectile is to the center of the block, the stronger the redstone signal that is produced.

Signal
The target provides temporary redstone charges for 20 ticks, similar to buttons and pressure plates, if hit with arrows or tridents, and for 8 ticks if hit with eggs, snowballs, splash potions, fire charges, firework rockets fired by a dispenser, lingering potions, bottles o' enchanting, ender pearls, or llama spit. The strength of the signal depends on how close the projectile is to the center of the block, from 1 to 15.

The target also provides a block update when hit, meaning that an observer can detect if the target has been hit and has produced a redstone signal.