Our JayFlight has a drain tube. It's unlikely defrost water is routed to a holding tank. It probably ends up in an open tray under or at the rear of the fridge for the water to evaporate.
We've used towels at the end of the season to soak up the defrost water before it drains anywhere.
I'm sure you'll hear from others before too long.
Sherm & Terry w/rescue Eydie (min Schnauzer) & Charley (std Poodle)
2015 Jay Flight 27RLS, GY Endurance (E), Days: 102 '15, 90 '16, 80 '17, 161 '18
2006 Ford F350 PSD, 4WD, CC, LB, SRW, Cmpr. pkg, Equal-i-zer 4-p, Continental ContiTrac TR