Not speaking for the host, but there is some general guidance on this topic that applies to most game jams.
If you’ve been coding for any length of time you’ll have a library of fairly generic functions you’ve written that apply to multiple projects. Maybe some of those functions were “borrowed” from stackoverflow originally. Some might be fairly large like a grid drawing and querying system or an animation system if the engine doesn’t provide one.
Bringing in the grid or animation systems is typically fine in most jams (not Ludum Dare), but a larger system that also includes character movement, and pre-programmed abilities that is nearly a playable game already, is not.
If it’s code you feel like you have to ask about–don’t do it