invasion_spawnpoint configuration

I took a look at the zulula map source and saw entities called invasion_spawnpoint. They are used for monster spawning. But they don't have any properties (well, except for angle). Are there any way to configure monster spawning? E.g. spawn specific kind of monsters using specific invasion_spawnpoint, set number of monsters, temporarily enable/disable invasion_spawnpoint and so on.
I tried to find something in entities.ent bundled in netradiant from xonotic mapping support, but it does not even list such entity.

I could be wrong but I pretty sure there were different entities or settings to spawn a different monster and there were more options when using the SMB mod but its been a while and Mario can answer that. I believe monsters can also follow a target so you can make them follow a path, I used that in the Miniman Invasion Map.