Explorer Note Index

[Anachron 0]

While looking through the official 15x15 ServerGrid.json file, I found several discovery zones with "explorerNoteIndex" values other than zero. The powerstones are one example for these. However, there are more and I got a lot of questions regarding them. There seems to be absolutely no explanation or information of them. Let's look at the "explorerNoteIndex": 2 for an example:

{"name": "Gorgon's Perch",
 "sizeX": 0.0,
 "sizeY": 0.0,
 "sizeZ": 0.0,
 "id": 2163,
 "xp": 0.0,
 "bIsManuallyPlaced": true,
 "ManualVolumeName": "Mnt_E_Near_02-GorgonsPerch",
 "explorerNoteIndex": 2,
 "allowSea": false,
 "worldX": 4900000.0,
 "worldY": 4900000.0,
 "rotation": 0.0}

It is located on the sever (3,3) and is shown in the center of the sever, which seems to be normal for manually placed discovery points. The name suggests, that it is located on the following island:

{"name": "Mnt_E_WF",
 "id": 863,
 "spawnerOverrides": {},
 "minTreasureQuality": -1.0,
 "maxTreasureQuality": -1.0,
 "useNpcVolumesForTreasures": false,
 "useLevelBoundsForTreasures": true,
 "prioritizeVolumesForTreasures": false,
 "islandTreasureBottleSupplyCrateOverrides": "",
 "worldX": 4542470.0,
 "worldY": 5304196.5,
 "rotation": -179.571625}

The coordinates, however, do not match the coordinates of the island. The coordinates of the power stone entries, in contrast, are definitely matching the PVE islands, while the coordinates of most "explorer notes" are located at the center of the server. Does anyone know what these "explorer notes" are and how they are enabled on private servers? Do I simply need an instance of Mnt_E on my map and put the discovery zone to the center of the server? Are they enabled on the official server, yet?