>>15135371He means if you put a Pokemon asking for one of those three, you can see that Pokemon when you search for it. For example, if you put up a Pikachu asking for a Hoopa, when you search for that Pikachu, you can find it and it will be asking for Hoopa in return.
If you do the same but with gibberish or fakemon names, it won't appear. Put up a Pikachu asking for Tentaquil or ASSHAT, and you won't be able to find that Pikachu when looking for a Pikachu at all.
