Click on "Anon" link under the "Obtained from:" line. There you'll see that this item is obtainable from Anon NPC for 10 Amity points.

You can get it by talking to NPC Anon, here you got a guide where to find him -> https://www.youtube.com/watch?v=Hx7rKgSAXDg

This image is either very out of date or was never correct in the first place, I have taken time to observe Anon's movements over an hour after I personally found him outside of the parameters put in place by this image from 2016, I have updated the image with my findings, there may be more but this is all I found in the time I invested into this
Blue = additional paths Anon can take
Green = spots Anon can idle at

The picture is almost correct! Anon teleports clockwise between the guard camps, there are four, including the village. He always stands a bit apart from the guards, the first picture with the guards was correct, just not well explained because he doesn't walk, but teleports

He can stop anywhere between each camp too. He changes locations roughly every 3minutes or so.

Fake info, NPC still available (SA server 2019)