Mysterious Voice-Overs?

My friend found this video and sent me the link: https://www.youtube.com/watch?v=eMBdnZgaYyQ (It's legit, I promise). Listen to the voice-overs. They're not in the game by any means, but it sounds like someone we know. A certain...Bandle Gunner with a badass attitude and rocking some scary-ass range. Yes, I'm talking about Tristana.

Listen to the voice-overs carefully. Then listen to Tristana's normal voice. It's spot-on.

So the question is: Legendary/Ultimate Skin or just some voice-over updates? I'd be interested in a Red response if possible, but I can understand if it's still top-secret.

(Also, please note that I didn't make the video, someone else did. I'm not taking credit, just trying to start a speculation thread.)