That seems reasonable enough. The zener and capacitor get charged to some peak voltage during the positive swing (through gate capacitance, I think?), while during negative swing, the transistor is turned on, shunting gate to -V quite aggressively (PBSSxxxx are quite powerful little transistors).
Turn-on will be limited by the 56Ω and transformer, so, pretty slow. This is reasonable for a ZVS resonant type inverter, and probably still isn't terrible for a square pulse type forward converter.
The transformer should output about 20V peak then, I think, and the transistor sees +15/-5 Vge (if it's more like a 5V zener as I would think to choose, but even a mere 2.4-2.7V will still help out a bit).
IGBTs tend not to turn off very well at Vge = 0, and some extra negative bias helps ensure turn-off.
Tim