Return 1 “Galaxy” or “Photon” monster from your hand to your Deck and add 1 “Galaxy” or “Photon” Spell/Trap Card from your Deck to your hand. This Skill can only be used if you begin the Duel with a Deck/Extra Deck that contains no monsters other than LIGHT monsters. This Skill can only be used once per Duel.
The skill update pretty much just allows you to play more rank 4s. Assuming they’re number cards.