Obvious Triples (Naked Triples), Explained

Six cells are open here and none of them shows a single color. Four of them show exactly two, which looks promising, but no two of those four show the SAME two, so there is no pair to find. A matching group can still be hiding. It just needs three cells instead of two.

Look at the three cells in this block’s right column together. The top cell shows Orange and Light Green. The middle cell shows Orange and Dark Purple. The bottom cell shows all three. Between them, only Orange, Light Green, and Dark Purple can go in these three cells, and there are exactly three cells, so those three colors fill them.

None of those cells is settled on its own, but the three of them together are. Only Orange, Light Green, and Dark Purple fit in them, so no other cell in the block can take any of the three. Light Green is the only one of the three written anywhere else, and it comes off both cells that show it.

The middle cell of the top row was showing Red and Light Green. Light Green belongs to the triple, so with it gone, only Red is left. Place it, and the Red note below comes off as it lands. The triple is no closer to being solved than it was, and it does not need to be.