How do I make overmap specials/terrains that only show up in debug?

Hello, everyone!

So, I just got back into CDDA, after over a year of not playing, and I’m trying to update a personal mod of mine that added in locations that don’t spawn automatically, but are available for manually placing via debug. The problem is, trying to do so is causing my game to immediately crash upon trying to place these locations, both via the overmap editor (placing in an unexplored square, of course) and via the map editor.

Given this, I’m thinking of just remaking them from scratch, using other overmap specials/terrains to guide me. However, those overmap specials/terrains are meant to spawn in during world generation, and given what I’ve already said, I obviously don’t want for that to happen.

Any help will be greatly appreciated. Thank you!

Just set the occurrences of you overmap special to [ 0, 0 ], and it won’t spawn naturally, only through debug menu.
Check \data\json\overmap\overmap_special\bordered_world.json for example of such OMS.

Overmap terrains won’t spawn in the world unless you assign them to some overmap special.

You can post here your problematic OMS and OMT and I’ll try to see what could be done.