I know and appreciate XKCD but I’m in no way an adept. What exactly a, I looking at? Warning; on Mobile Safari I succeeded in zooming in by enlarging part of t

I know and appreciate XKCD but I’m in no way an adept. What exactly a, I looking at? Warning; on Mobile Safari I succeeded in zooming in by enlarging part of the surrounding page and recentering, but then I couldn’t zoom out.