While the player has rested experience, this addon will display the amount of rested experience remaining, how many kills until that rested experience is used up, and how many kills until the character reaches the next level. It will not show anything unless the amount of rested experience changes, so it will not display when turning in quests or if the player is no longer rested. This is V1.x only. If you prefer this format, install v1.2.
V2 now shows all levels that can grant XP to the character (up to 4 levels above, since XP caps there), how much XP will be granted on a solo kill of that level, and how many kills are needed to use up all rested XP.