LibWaypoint-1.0 is a library to provide an agnostic system for both waypoint producers (addons that point to things) and waypoint consumers (addons that actually show an arrow on the screen/map/minimap/etc.)
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A library to provide unit-oriented tags to LibDogTag-3.0
A library to provide a markup syntax
A library to handle rearrangement of blizzard's frames when bars are added to the sides of the screen.
A library to provide information about zones and instances.