I just noticed this info on the xkcd website for the first time:
xkcd.com is best viewed with Netscape Navigator 4.0 or below on a Pentium 3±1 emulated in Javascript on an Apple IIGS at a screen resolution of 1024x1. Please enable your ad blockers, disable high-heat drying, and remove your device
from Airplane Mode and set it to Boat Mode. For security reasons, please leave caps lock on while browsing.
It unlocks your screen rotation settings and links screen orientation to the phones gyroscopic sensor to maintain orientation perpendicular to the horizon.