Urmm, going by the filename ("GIFEncoder.class.php"), that's just the GIF Encoder. This post isn't about the ability to generate GIFs using PHP (as that class does), but about varying the content of the GIF on a per-request basis (in "real-time").
Looking at the git commit history, this was created ~2 days ago.
Looking at the git commit history, this was created ~2 days ago.