https://www.curseforge.com/wow/addons/project-19341 [ 1 ] was http://wow.curseforge.com/addons/mapruler/
While looking at the map, a ruler is drawn out the front of your position-arrow. Helpful for seeing the arrow more easily.
A fork to update it is https://www.curseforge.com/wow/addons/mapruler-continued [ 2 ] was https://wow.curseforge.com/addons/mapruler-continued/