Leatrix Maps reveals the entire world map (i.e. removes the fog of war) and shows dungeon location icons on the map.
Enter /ltm to open Leatrix Maps. Some options have little configuration buttons next to them for further configuration.
Always read the change log when installing updates.
For a few helpful guides, click here.
If you wish to report an issue or make a suggestion, make a ticket here.
If you are looking for Leatrix Maps for Battle for Azeroth, it's here.