Plague Plaque

Plague Plaque is found at on the tree trunk in front of the bridge to Corin's Crossing in the Eastern Plaguelands. It is only seen after unlocking the Tricked-Out Thinking Cap from the Secrets of Azeroth event. If the cap is not already worn, interacting with the plaque will equip it.

It reads:

The plaque has a typo, as the intended location is (15, 15) at north of a house in Corin's Crossing, which has a Loose Dirt Mound that contains a Buried Satchel for Community Rumor Mill.