Has 3 modes - Lines, Lines-Thin, Arrowless.
Mod supports both base Factorio and Space Age.

This mod was initially conceived to reduce the flickering of belt arrows by simply removing the arrows with no additional changes, but while doing that I decided to try adding a line, and it looks great in my opinion.

The mod does not affect any prototype values apart from "filename", so it should be compatible with everything that modifies default belts.
Feel free to adapt to your mod and your own belts.