@KeliosFR is the leaker who correctly predicted the announcement of the Diamond and Pearl remakes, and was one of the first people to post footage of the games prior to their official unveiling.
The last Pokémon Presents we got was in February of this year, which revealed the existence of the aforementioned Diamond and Pearl remakes. We've also had presentations of this type around E3 time, so it's highly likely this rumour is legit. Perhaps you disagree? Let us know with a comment.