Blank Target

From FFXI Wiki

The kissing cousin of the ??? spot. A Blank Target is simply that, a location that is targetable but has no name. They were first used in the final forms of relic weapons, but are also used in other quests. Occasionally they will have a glowy, shimmery aura but most of the time they are completely inconspicuous and would never be noticed except for random tabbing.

Like the ??? spot, touching one will give you a message, normally "There is nothing out of the ordinary here", unless it is needed for a quest that you are currently on.