Seems it shows up each time the site tries to play short audio clips. See starting line 32 in http://www.jurassicsystems.com/js/jurassicSystems.js Instead of feature detection it'll use HTML5 audio in Chrome, show an annoying dialog in Safari, and an SWF fallback for anything else.
edit: Here's the GitHub issue for it https://github.com/tojrobinson/jurassicsystems.com/issues/1