In Chrome mobile there is a small box on the address bar that shows how many tabs you have open. I've had it at rather large number for a long while, steadily creeping up. But a few days ago I noticed it didn't display a number anymore - just ":D".
First I was a bit confused. It's a feature that has been there that I haven't paid that much attention so first I didn't even remember it was there. I was just wondering what that means. After a moment I realized it's the box where the tab count used to be. But why didn't show the count anymore? Just that weird emoji.
Turns out that's an easter egg (or just overcoming the fact the design only allows 2 digits to fit in the box). It turns into that when you have over 99 tabs open! Yes, I'm a tab hoarder :D