The bug
Entity target arguments of commands can be tab-completed with the UUID of the entity in the player's crosshair. This does not work for projectiles.
How to reproduce
Shoot an arrow into the ground
Look at it
Type
/data get entity
and see what tab suggestions are offered
Linked issues
relates to 2
Attachments
Comments 13
Strangely, it does not affect ghast fireballs (but does affect small fireballs and dragon fireballs)
Same cause as for MC-46621. Note that this is now the method
Entity.isPickable()
(20w10a Mojang name) which controlls whether an entity is considered a hit result (though it is also used for other purposes).