This meetup is very informal - it is a show up, have a coffee and chat about work kind of thing.
Basically, it's all about making your systems and services more reliable, so typical topics might be configuration management, deployment, monitoring or the quirks of deploying on AWS/Google Compute Engine/Azure or private hardware, whether in a server room or a data center, but the discussion is really up to whoever is there.
I'm the tall guy with a goatee and a light brown leather backpack. If other people haven't shown up yet I'll have my laptop out and the lid is encrusted with tech stickers. I'm hard to miss.
Don't feel you have to stay for the whole two hours - show up when you can, get your caffeine, stay as long as you want, then go.