Ross Tuck is originally from the USA but now lives in the Netherlands and works for Castor. He runs the Tactician open source project, is one of the founders of the DomCode usergroup and has run the DomCode conference on several occassions. On top of that, he is a conference speaker.
Sebastian comes from Germany, where he has been developing for 20 years. He is currently teamlead webdevelopment at CHECK24. He also contributes to open source software and can be found as a speaker at conferences in several different countries.
Thomas is a developer at NetAnts in the southern Dutch province of Limburg. He also teaches kids to program and likes to dabble with Virtual Reality and 3D printing.
James is that nice bloke working at Roave (I think they only have nice blokes there, but I could be mistaken). He is one of the founders of the PHP South Coast conference and has run the PHP Hampshire usergroup for a long time.
Mark Baker is senior software engineer at MessageBird, but also serial contributor to the PHP community. He maintains the PHPOffice library and is also the person responsible for Enfys, the Rainbow elePHPant.