Depends honestly, Mod Alex's Necromancer tower is a good example.
It was worked on as part of the previous game jam and naturally fit with Necromancy's launch so it got extra resources to get done in time for the launch.
Most of the time a Game Jam project has to go through a few iterations at Jams to get to a state where it is ready to push forward on. So often a bunch of projects get the push at around the same time and get worked into the upcoming content timeline so like updates to combat things may get picked up while combat is a focus etc.
There is a lot of behind the scenes work that goes into each project and they all take a varying amount of time to finalize so generally they come out when they are ready.