I learned about it from a member of the BTT forum some time ago, and it just proves that every day we can learn something new using the forum.
You are right, there are many things that I came to know some time ago while I was on BTT for a long time. For example, after making the post, I never thought what the bottom button (modify button) would do, and in 2023 I guess I saw on someone's post, the purpose of that button. I was shocked to see that. There are many other things that I did not know but with time came to know about them. For example here on this forum, I use the mouse to open a new tab, and I use ctrl+Left click to open a new tab, but this key doesn't work when we are opening a quote tab. What we have to do is ctrl+scroll key on the mouse.
And now this emoji thing. I guess there are many other things are on the roadmap which came to our eyes when the time was right hehe.
I've had a favorite when it comes to emojis for a long time, and it's not bad to save it in favorites 
https://www.piliapp.com/facebook-symbols/
Favoutrite what? emoji or website to copy emoji. I asked because you mentioned the link, not the emoji. I hope I have not asked a dumb question 😅