I hope it's earlier im on aflight to MCO leaving 630 am this Friday with car service dropping me off at YYZ at 4:15 am..although im sure with all the delays this week that it's hgihly unlikely we'll take off on time anyway
I did a bit more searching around and I've found two different answers.
4-45am and 5am.
Not sure which one (if any) is accurate.
I've sent a message to GTAA to ask.