Twitch the 19 in front of the name?

Hello today I see several names chatting with a 19 (extra symbol) in front of the name what does that mean and how do I get the self

That's what you get when you buy tickets for TwitchCon in San Diego for this year.

Thank you

Small correction: You mean Berlin instead of San Diego. For San Diego, as far as I can see, there are no tickets yet.