That's correct, he said he likes the size of the GB2 trap but wanted to include some of the GB1 trap features, so it's effectively a hybrid trap.
Here's his RPF thread about it: https://www.therpf.com/forums/threads/3 ... vy.258673/
As a belt hanger it's ideal, it's strong but lightweight (like a stunt trap). The upgrade parts he offers on his Etsy store are worth a look too, especially the acrylic and aluminium side plates.
If you ever need a trap with an ejectable cartridge, check out the TacoBelli files for sale on Etsy, these are larger but include options for GB1, GB2, and Afterlife.
Here's a size comparison between the Sean Charlesworth trap and my in-progress TacoBelli trap:
Personally I like both for different reasons. My TacoBelli trap is now far too heavy to hang from my belt, but it's perfect to sit on the table at events. With the opening doors, lights and sounds, and the ejecting cartridge it's great for demonstrations too. When I eventually build a containment unit this is the one I'll use with it.