FEBuilder is giving you partially incorrect information. This text entry is referenced by its text ID used in the table of terrain names, and FEBuilder gives you the correct address for this, 0x80D376; this is the location within that table where this text entry’s ID is located. However, it is labeled in the editor as a Unit and takes you to a unit when you double-click it (it also says Unit 0x01 and takes you to Unit 0x02, Seth, when double-clicked).
The editor for terrain names is called Tile Names, you can change what text IDs are used for every terrain name there