The "World Border Warning" effect is awesome. It looks cool, and is very useful for mapmaking.

!World Border Warning

But when you enable the "Vignette" option to see the warning effect, your Minecraft has this annoying vignette effect:

!Annoying Vignette

This simple mod removes the vignette effect while keeping the world border warning effect, so you can use the amazing effect in your maps without being annoyed by the vignette effect!