An incredibly trivial little 3D-printed accessory for your Anycubic Linear Plus... that makes it reassuringly easy to see at a glance how filament is feeding/retracting. This little pointer (seen in light blue here) simply pushes onto to shaft of the E-axis motor and spins with it. Would probably work on many Bowden-tube feeders....
Trivial print. Use a color that stands out against the black of the E drive unit.