Purpose:
This will let you modify an item's enchantments, gems, and sometimes suffix to create fake item links. You can then send those links in messages for your own strange purposes.
Using:
To start modifying an item, use the command: /ill <item link or item ID>
You can also drag an item to the window once it's open.
If you set a 2nd enchantment, shift-clicking the link to send it somewhere else will cause that enchantment to be removed, so you won't be able to use "Create Link" then use it in messages. Instead, there's a chat command line to send a link directly in a message. Add [link] anywhere in the message and it will change that to the real fake link. For example, to whisper Baloo: /w Baloo After 12 runs [link] finally dropped
A suffix can only be set on items that normally have them, and those items must be opened by either using /ill <item link> or by dragging the item to the window. The item link has to actually have a suffix too and not be a base link without one from AtlasLoot or something like that. With TBC items, each item seems to only allow a certain group of suffixes to be used or else the link will just become plain text. Vanilla items didn't seem to have this restriction but I didn't test many. You should probably send a whisper to yourself to test if the new suffix works before trying to use it somewhere.