Doing this also causes the screen to spin in a dizzying fashion. When it stops, you'll be greeted to a sepia makeover of your browsing window. If you recall, the beginning of The Wizard of Oz was in black and white, before Dorothy gets caught up in a tornado and transported to the colorful world of Oz.
You can scroll down while the browser window maintains its sepia tone, though it quickly disappears whenever you click on a link or navigate to a new page. Additionally, you can click or tap on the floating tornado that takes the place of the ruby red shoes, and the screen will spin once again, restoring the normal color tone.
Be warned, though—if you are prone to dizziness, you should probably skip this particular Easter Egg (or at least close your eyes for a few seconds after clicking). That said, this works on both desktop and mobile, and in any browser.
This is reminiscent of the Avengers: Endgame Easter Egg, which is still available. If you perform a search for Thanos, there is a clickable Infinity Gauntlet (or "glove," if you prefer) in the same spot as the ruby red slippers. Clicking it causes part of the browser window to go up dust. while a subsequent click restores the disintegrated contents. This still works, by the way.